Primer on U.S. Immigration Policy

Congressional research reportMar 31, 2025

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R45020

SUMMARY

Primer on U.S. Immigration Policy

U.S. immigration policy is governed largely by the Immigration and Nationality Act (INA),

which was first codified in 1952 and has been amended significantly several times since. U.S.

immigration policy contains two major aspects. One facilitates migration flows of foreign

nationals into the United States; another focuses on immigration enforcement and removal.

Immigration functions authorized by Congress in the INA and other laws are carried out by

several executive branch departments and agencies.

R45020

March 31, 2025

Holly Straut-Eppsteiner

Analyst in Immigration

Policy

The United States has long distinguished permanent from temporary immigration. The INA’s

permanent immigration categories reflect principles of admission that are based upon national interest, including family

reunification, U.S. labor market contribution, origin-country diversity, and humanitarian assistance. The INA provides lawful

permanent resident (LPR) status through family and employer-sponsored categories, the diversity immigrant visa, and grants

of refugee status and asylum, among others. LPRs may choose to naturalize, or become U.S. citizens, upon meeting

requirements specified in the INA. Temporary immigration occurs through the admission of foreign nationals for specific

purposes and limited periods of time, and encompasses two dozen categories that include foreign tourists, students,

temporary workers, and diplomats.

The executive branch may exercise statutory or executive authority to allow certain noncitizens to enter or remain in the

United States on a time-limited basis, including those who have not been admitted through permanent or temporary pathways

under the INA and might otherwise be subject to removal. These include Temporary Protected Status (TPS), immigration

parole, and Deferred Action for Childhood Arrivals (DACA).

The INA also provides authority for immigration enforcement, including restricting entry to and removing persons from the

United States who lack authorization to be in the country or who have such authorization but have committed acts that make

them subject to removal. Immigration enforcement functions include border enforcement, interior enforcement, detention,

and removal. Some individuals subject to removal may be repatriated; others may be eligible for forms of permanent relief or

temporary protection from removal.

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Contents

Introduction ..................................................................................................................................... 1

Immigration Inflows and Related Topics ........................................................................................ 1

Visa Issuance and Security ........................................................................................................ 1

Permanent Immigration ............................................................................................................. 3

Requirements for Prospective Immigrants .......................................................................... 4

Family-Sponsored Immigration .......................................................................................... 5

Employment-Based Immigration ........................................................................................ 5

Diversity Immigrant Visa .................................................................................................... 6

Refugees and Asylees ......................................................................................................... 7

Other Pathways to LPR Status ............................................................................................ 8

Naturalization ............................................................................................................................ 9

Temporary Immigration .......................................................................................................... 10

Discretionary Permissions to Enter or Remain in the United States ........................................ 11

Temporary Protected Status ............................................................................................... 11

Deferred Enforced Departure ............................................................................................ 12

Immigration Parole ........................................................................................................... 12

Deferred Action for Childhood Arrivals ........................................................................... 12

Immigration Enforcement ............................................................................................................. 13

Border Enforcement at Ports of Entry ..................................................................................... 13

Border Enforcement Between Ports of Entry .......................................................................... 14

Interior Immigration Enforcement .......................................................................................... 15

Detention and Case Management............................................................................................ 16

Removal Processes .................................................................................................................. 17

Defenses Against Removal ............................................................................................... 18

Tables

Table 1. Family-Sponsored Immigrant Categories .......................................................................... 5

Table 2. Employment-Based Immigrant Categories........................................................................ 6

Contacts

Author Information........................................................................................................................ 20

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Introduction

U.S. immigration policy is governed largely by the Immigration and Nationality Act (INA),

which was first codified in 1952 and has been amended significantly several times since.1

Implementation of the provisions in the INA and other laws, including the Homeland Security Act

of 2002 (HSA; P.L. 107-296.), is carried out by executive branch agencies. The Department of

Homeland Security (DHS), established under the HSA, has primary responsibility for

immigration functions through its component agencies: U.S. Citizenship and Immigration

Services (USCIS), U.S. Customs and Border Protection (CBP), and U.S. Immigration and

Customs Enforcement (ICE). The Department of State (DOS) issues visas to foreign nationals

overseas through its Bureau of Consular Affairs and manages the U.S. Refugee Admissions

Program through its Bureau of Population, Refugees, and Migration. The Department of Justice

(DOJ) operates immigration courts through its Executive Office for Immigration Review (EOIR).

Immigration courts adjudicate immigration hearings, including removal proceedings. The

Department of Health and Human Services’ (HHS’) Office of Refugee Resettlement (ORR)

oversees refugee resettlement and is responsible for the care and custody of unaccompanied

children. The Department of Labor (DOL) operates a foreign labor certification program to

enforce laws intended to ensure that foreign workers do not displace or adversely affect wages or

working conditions of U.S. workers.

This report provides a broad overview of U.S. immigration policy. The first section addresses

laws and policies governing how foreign nationals (aliens2) may enter the United States to either

reside permanently or stay temporarily. Related topics within this section include visa issuance

and security, naturalization (i.e., the process of obtaining U.S. citizenship), and discretionary

permissions to enter or remain in the United States. The second section discusses enforcement

policies for excluding certain foreign nationals from admission into the United States and for

detaining and removing those who enter the country unlawfully or who enter lawfully but are

charged with one of the INA’s grounds of deportability. While intended to be comprehensive, this

primer may omit some immigration-related topics.

Immigration Inflows and Related Topics

Visa Issuance and Security

In general, nonresident foreign nationals who wish to come to the United States—either as lawful

permanent residents (LPRs) through permanent family-sponsored, employment-based, and

diversity categories; or as nonimmigrants through temporary pathways—must obtain a visa from

a U.S. consulate.3 Immigrant visas provide for permanent residence; nonimmigrant visas provide

for temporary stays. A visa permits a foreign national to travel to a U.S. port of entry and request

permission from CBP to enter the country (i.e., apply for admission). In addition, to obtain a visa

1 The Immigration and Nationality Act (INA, P.L. 82-414) is codified, as amended, at 8 U.S.C. §§1101 et seq.

2 The INA defines “alien” as a person who is not a citizen or a national of the United States. INA §101(a)(3); 8 U.S.C.

§1101(a)(3). In this report, the terms alien, foreign national, and noncitizen are synonymous.

3 Exceptions include citizens or nationals of the (currently) 42 Visa Waiver Program (VWP) designated countries,

Canadian USMCA Professional Workers, and citizens of Canada and Bermuda; 8 C.F.R. §212.1. For more information,

see CRS Report RL32221, Visa Waiver Program; and DOS, “Travel Without A Visa,” https://travel.state.gov/content/

travel/en/us-visas/tourism-visit/travel-without-a-visa.html.

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a foreign national must establish that he/she meets the requirements for the specific visa

classification. Consular officers can deny visas under three main INA provisions:

1. insufficient information under INA Section 221(g),

2. grounds of inadmissibility under INA Section 212(a), and

3. for nonimmigrant applicants, the INA Section 214(b) presumption of seeking

permanent residence.

A visa denial under INA Section 221(g) indicates that the DOS consular officer abroad lacks

sufficient information to determine if a foreign national is eligible to receive a visa. A consular

officer may also disqualify a visa applicant if (1) he/she knows or has reason to believe the alien

is inadmissible under INA Section 212(a) (described below) or any other provision of law, or (2)

the application fails to comply with INA provisions or regulations. A visa denial under INA

Section 214(b) indicates that the foreign national was unable to demonstrate to the consular

officer that he/she had sufficient ties to his/her home country to return home.4 This is the most

common reason that DOS denies nonimmigrant visas.

Consular officers must decide whether a foreign national may be denied admission to the United

States under the grounds in INA Section 212(a), which include the following:

•

health-related grounds,

criminal grounds,5

security and terrorist concerns,

public charge risk (e.g., indigence),6

seeking to work without proper labor certification,

lacking valid entry documents,

previous illegal U.S. entry and U.S. immigration law violations,7

ineligibility for U.S. citizenship, and

having been previously removed from the United States.8

The INA describes procedures for making and reviewing an inadmissibility determination and

specifies conditions under which some of these provisions may be waived.

All visa applicants are required to submit their photograph, fingerprints, and biographic

information. Visa applicants are checked against multiple databases and information sources for

security purposes. All prospective LPRs and certain prospective nonimmigrants must also submit

to physical and mental examinations. Visa applicants generally must be interviewed by a consular

officer in person to determine whether they are qualified to receive a visa.9 Consular officers’

4 Some nonimmigrant visas, including those for H-1B specialty occupation workers, L intracompany transferees, K

fiancés, and V accompanying family members allow visa holders to simultaneously seek LPR status.

5 For more information, see CRS Report R45151, Immigration Consequences of Criminal Activity.

6 For more information, see CRS In Focus IF11467, Immigration: Public Charge; and CRS Legal Sidebar LSB10341,

DHS Final Rule on Public Charge: Overview and Considerations for Congress.

7 With certain exceptions, persons who depart the United States after being unlawfully present for more than 180 days

but less than one year are subject to a 3-year bar on admission; those who depart after being unlawfully present for at

least one year are subject to a 10-year bar. INA §212(a)(9)(B); 8 U.S.C. §1182(a)(9)(B).

8 For more information, see CRS In Focus IF12662, Immigration: Grounds of Inadmissibility.

9 See INA §222(h), 8 U.S.C. §1202(h) and 22 C.F.R. §41.102 (requirements for nonimmigrant interviews), and 22

C.F.R. §42.62 and DOS, “Immigrant Visa Process,” https://travel.state.gov/content/travel/en/us-visas/immigrate/the(continued...)

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decisions on whether or not to grant foreign nationals a visa are not subject to judicial appeals.

Visa applicants who were denied a visa for a particular ineligibility and meet certain conditions

may apply to DHS for a waiver of that ineligibility and apply again for a visa.

The INA has civil enforcement provisions, distinct from removal or inadmissibility proceedings,

to prosecute individuals and entities that engage in immigration document fraud.10 Apart from the

INA, the U.S. Criminal Code classifies knowingly producing or using fraudulent immigration

documents (e.g., visas, border crossing cards) as criminal offenses.11

Permanent Immigration12

The permanent immigration system provides foreign nationals with LPR status (commonly, a

green card).13 Four major principles underlie the current system of permanent immigration:

family reunification, U.S. labor market contribution, origin-country diversity, and humanitarian

assistance. These principles are reflected in the different categories that provide LPR status under

the INA. Family reunification occurs primarily through family-sponsored immigration. U.S. labor

market contribution occurs through employment-based immigration. Origin-country diversity is

addressed through the diversity immigrant visa. Humanitarian assistance occurs primarily through

the U.S. refugee program and asylum. These permanent immigration pathways are discussed

further below.

The INA limits worldwide permanent immigration to 675,000 persons annually: 480,000 familysponsored immigrants, made up of immediate relatives of U.S. citizens, and a set of ordered

family-sponsored preference immigrants (preference immigrants); 140,000 employment-based

immigrants; and 55,000 diversity visa immigrants.14 These numerical limits include spouses and

children who accompany the principal immigrants.

This worldwide limit, however, is referred to as a permeable cap because immediate relatives are

exempt from numerical limits that are placed on family-sponsored immigration (described below)

and thereby represent the flexible component of the 675,000 worldwide limit. In addition, the

annual number of refugees is determined not by statute but by the President in consultation with

Congress. Applications for asylum are adjudicated on a case-by-case basis without a statutorily

mandated limit (see the “Refugees and Asylees” section). Consequently, the actual total number

immigrant-visa-process/step-10-prepare-for-the-interview/step-11-applicant-interview.html (requirements for

immigrant visas).

10 INA §274C; 8 U.S.C. §1324c.

11 18 U.S.C. §1546.

12 In this report, the term admissions broadly refers to the entry of aliens into the United States, either permanently or

temporarily. Technically, aliens who immigrate permanently do so either by being admitted as LPRs (if arriving from

abroad) or by adjusting status from a temporary status to LPR status (if residing in the United States). For more

information on permanent immigration, see CRS Report R42866, Permanent Legal Immigration to the United States:

Policy Overview.

13 In this report, the terms immigrant, lawful permanent resident, and green card-holder are synonymous.

14 See, respectively, INA §201(c), INA §201(d), and INA §201(e). While the diversity visa category has not been

directly amended since its enactment, the Nicaraguan Adjustment and Central American Relief Act of 1997

(NACARA; P.L. 105-100) temporarily reduced the 55,000 annual ceiling beginning in FY1999 by up to 5,000 annually

to offset immigrant numbers made available to certain unsuccessful asylum seekers from El Salvador, Guatemala, and

formerly communist countries in Europe. In addition, the National Defense Authorization Act for Fiscal Year 2024

(P.L. 118-31) makes additional special immigrant EB-4 visas available for current or former employees of the U.S.

government abroad who have at least 15 years of service (up to 3,500 in FY2024 and 3,000 in subsequent years). To

ensure that no immigrant visas are issued beyond current total INA limits, the bill reduces the number of diversity visas

available each year by the same number of EB-4 visas issued under this provision.

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of persons who receive LPR status annually has exceeded 1 million in all but 3 of the past 20

fiscal years.

To ensure that foreign nationals from only a few countries do not dominate permanent

immigration flows, the INA further specifies a 7% per-country limit on the number of familysponsored preference immigrants and employment-based immigrants.15

Requirements for Prospective Immigrants

To obtain LPR status, prospective immigrants undergo a multistep process through several federal

departments and agencies.16 If they are present in the United States, they apply for LPR status by

adjusting status, typically from certain nonimmigrant (temporary) statuses to LPR status. If they

are outside the United States, they apply for an immigrant visa at a U.S. consulate. All familybased immigrants and most employment-based immigrants require a relative or an employer,

respectively, to petition on their behalf. Petitions are submitted to and adjudicated by USCIS.

Petitions filed on behalf of a visa applicant outside the United States are first adjudicated by

USCIS and then forwarded to DOS’s Bureau of Consular Affairs in the prospective immigrant’s

home country for immigrant visa processing. Most immigration petitions and applications require

fees.17

For all prospective immigrants, the USCIS adjudicator (when the alien is adjusting status within

the United States) or USCIS and the consular officer (when the alien lives abroad) must be

satisfied that prospective immigrants are entitled to LPR status and are not ineligible under the

INA’s grounds of inadmissibility (see the “Visa Issuance and Security” section).18

The number of foreign nationals seeking to acquire LPR status each year through familysponsored and employment-based preference categories typically exceeds the INA-mandated

numerical limits for these pathways. Apart from the numerical limits that apply to prospective

immigrants from all countries, the 7% per-country cap primarily affects foreign nationals from

countries that send relatively large numbers of immigrants to the United States (e.g., Mexico,

China, India, the Philippines). As a result, many foreign nationals who qualify for LPR status may

have to wait years before a numerically limited green card becomes available.

DOS manages the numerical control of green cards according to the INA’s limitations.19 When a

numerically limited green card becomes available, an approved prospective immigrant may apply

for an immigrant visa to travel to the United States and, if admitted at a U.S. port of entry by a

CBP immigration officer, receive LPR status. If the approved prospective immigrant already

resides in the United States as a temporary nonimmigrant, the availability of a green card allows

15 This means that the total number of (numerically limited) family-sponsored preference immigrants and employment-

based immigrants from a single country each year is limited by this provision to 7% of the total (226,000 plus 140,000)

or 25,620. For more background, see CRS Report R42866, Permanent Legal Immigration to the United States: Policy

Overview.

16 For more information, see CRS Report R42866, Permanent Legal Immigration to the United States: Policy

Overview.

17 USCIS, which processes and adjudicates most immigration-related applications and petitions, operates largely on fee

revenue. A fee schedule for all applications and petitions can be found at https://www.uscis.gov/g-1055. For

background information, see CRS Report R48021, U.S. Citizenship and Immigration Services (USCIS): Operations

and Issues for Congress.

18 For more information, see CRS In Focus IF12662, Immigration: Grounds of Inadmissibility.

19 For more information, see DOS, “The Operation of the Immigrant Numerical Control System,”

https://travel.state.gov/content/dam/visas/Immigrant%20Visa%20Control%20System_operation%20of.pdf.

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him/her to adjust to LPR status without having to return to his/her country of origin to complete

visa processing at a DOS consulate.

Family-Sponsored Immigration

Family-sponsored immigration comprises two groups (Table 1). Immediate relatives include

spouses and minor unmarried children of U.S. citizens and parents of adult (ages 21+) U.S.

citizens. Immediate relatives are not subject to annual numerical limits and can acquire LPR

status if they meet the standard eligibility criteria required of all immigrants. Preference

immigrants are numerically limited to 226,000 per year and, unlike immediate relatives, are also

bounded by the 7% per-country limit.20 From FY2014 to FY2023, family-sponsored immigrants

accounted for 64% of all persons receiving LPR status.21

Table 1. Family-Sponsored Immigrant Categories

Category

Individuals in Category

Numerical Limit

1st Preference

Priority workers: persons of extraordinary

ability in the arts, sciences, education,

business, or athletics; outstanding professors

and researchers; and certain multinational

executives and managers

28.6% of total EB limit (40,040) plus unused

4th and 5th preference visas

2nd Preference

Members of the professions holding advanced

degrees or persons of exceptional ability in

the sciences, arts, or business

28.6% of total EB limit (40,040) plus unused

1st preference visas

3rd Preference

Skilled shortage workers with at least two

years training or experience, and

professionals with baccalaureate degrees; and

“other (unskilled shortage) workers”

28.6% of total EB limit (40,040) plus unused

1st or 2nd preference visas; “other workers”

limited to 10,000.

4th Preference

Special immigrants, including ministers of

religion, religious workers other than

ministers, certain employees of the U.S.

government abroad, and others

7.1% of worldwide limit (9,940); religious

workers limited to 5,000 and broadcasters

limited to 100.a

5th Preference

Employment creation investors who invest at

least $1.05 million ($800,000 in rural areas,

areas of high unemployment, or infrastructure

projects) and create/preserve at least 10 U.S.

jobs

7.1% of total limit (9,940);

3,000 minimum reserved for investors in rural

or high unemployment areas

Source: INA §203(b), 8 U.S.C. §1153(b).

a. Congress has made available additional visas in this category to certain employees of the U.S. government

abroad for whom visas are not immediately available by offsetting the number of diversity visas. See

footnote 14 and CRS Report R47164, U.S. Employment-Based Immigration Policy.

Diversity Immigrant Visa

The diversity immigrant visa fosters legal immigration from countries that send relatively few

immigrants to the United States.25 Each year, 55,000 visas are made available to nationals of

countries from which immigrant admissions totaled less than 50,000 over the preceding five

years. Since the visa’s inception in the early 1990s, the regional distribution of diversity

22 For a complete list of special immigrant categories, see USCIS, “Employment-Based Immigration: Fourth Preference

EB-4,” at https://www.uscis.gov/working-in-the-united-states/permanent-workers/employment-based-immigrationfourth-preference-eb-4.

23 The EB-5 visa was created through the Immigration Act of 1990 (P.L. 101-649). For more background, see CRS

Report R44475, EB-5 Immigrant Investor Program.

24 For more information, see CRS Report R42866, Permanent Legal Immigration to the United States: Policy

Overview.

25 INA §203(c); 8 U.S.C. §1153(c). For more information about diversity visas, see CRS Report R45973, The Diversity

Immigrant Visa Program.

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immigrants has shifted from Western European to African, Eastern European, and Asian

countries.26

To be eligible for a diversity immigrant visa, foreign nationals must have a high school education

or two years of work experience within the past five years in an occupation that requires at least

two years of training or experience. Because the demand for diversity visas is much higher than

the supply, a lottery is used to randomly select who may apply for one. To receive a diversity visa,

lottery selectees must successfully complete the application process (including security and

medical screenings and in-person interviews) by the end of the fiscal year for which they

registered for the lottery; otherwise, they lose their eligibility.27

Refugees and Asylees

Refugees are processed and admitted to the United States from abroad. A refugee is a person who

is typically outside their country and is unable or unwilling to return because of persecution, or a

well-founded fear of persecution, on account of race, religion, nationality, membership in a

particular social group, or political opinion.28 DOS’s Bureau of Population, Refugees, and

Migration coordinates and manages the U.S. Refugee Admissions Program; USCIS interviews

applicants and makes final eligibility determinations. DOS sets annual refugee priorities in

collaboration with other agencies.29

Refugee status is granted within numerical limits. Refugee admissions differ from other

immigrant admissions because they have no statutory numerical limitations. The INA authorizes

the President, in consultation with Congress, to set an annual “refugee ceiling.” Refugee ceilings

and admissions have varied over time.30 Examining the last 10 fiscal years, the refugee ceiling

ranged between 15,000 in FY202131 (the lowest on record) and 125,000 in FY2025.32 During that

period, refugee admissions ranged between a low of 11,411 in FY2021 to a high of 100,034 in

FY2024.33 After one year in refugee status, refugees are required to adjust to LPR status.34 There

are no numerical limits on status adjustments for refugees.

An asylee is a person who meets the definition of a refugee in terms of persecution or a wellfounded fear of persecution but is present in the United States or at a land border or port of entry

to the United States.35 Under the INA, aliens who are physically present in the United States or

26 See archived CRS Report R45102, Diversity Immigrants’ Regions and Countries of Origin: Fact Sheet and DHS

Office of Homeland Security Statistics, 2023 Yearbook of Immigration Statistics.

27 Such individuals may register for the lottery again in subsequent years.

28 INA §101(a)(42); 8 U.S.C. §1101(a)(42). While persons seeking refugee status often reside in a second country that

is neither their home country nor the United States, some reside in their home countries in certain circumstances. See

§101(a)(42)(B); 8 U.S.C. §1101(a)(42)(B).

29 For more information about refugee admissions, see CRS Report R47399, U.S. Refugee Admissions Program.

30 For annual refugee ceilings and admissions from FY1981 through FY2022, see Appendix A in CRS Report R47399,

U.S. Refugee Admissions Program.

31 The White House, “Presidential Determination on Refugee Admissions for Fiscal Year 2021,” 85 Federal Register

71219-71221, November 6, 2020. In May 2021, President Biden issued an emergency presidential determination to

raise the FY2021 refugee ceiling to 62,500. See The White House, “Memorandum for the Secretary of State on the

Emergency Presidential Determination on Refugee Admissions for Fiscal Year 2021,” May 3, 2021.

32 The White House, “Presidential Determination on Refugee Admissions for Fiscal Year 2025,” 89 Federal Register

83767, September 30, 2024.

33 DOS, Bureau of Population, Refugees, and Migration, “Summary of Refugee Admissions as of October 31, 2024,”

https://www.wrapsnet.org/admissions-and-arrivals/.

34 INA §209(a); 8 U.S.C. §1159(a).

35 INA §208(a)(1); 8 U.S.C. §1158(a)(1).

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who arrive in the United States may apply for asylum regardless of their immigration status,

subject to certain restrictions.36 A person who is not in removal proceedings may apply for

affirmative asylum with USCIS.37 Persons in removal proceedings may apply for defensive

asylum (i.e., asylum as a defense against removal) in immigration court (within DOJ’s EOIR).38

Grants of asylum are not numerically limited. Asylees may apply for LPR status one year after

being granted asylum. 39 There are no numerical limits on status adjustments for asylees.

Other Pathways to LPR Status

In addition to the primary components of permanent immigration discussed above, the INA

contains several other pathways to LPR status, though they account for relatively few immigrants

each year. The most prominent among these are cancellation of removal, U nonimmigrant visas,

and T nonimmigrant status.40

Cancellation of removal is a discretionary form of relief granted by an immigration judge to

aliens in removal proceedings and is available to certain LPRs and non-LPRs.41 Non-LPRs

granted cancellation of removal are granted LPR status. To qualify for cancellation of removal

and adjustment of status, a non-LPR must have been continuously physically present in the

United States for at least 10 years, have been a person of good moral character, have not been

convicted of certain enumerated criminal offenses, and establish that their removal would result

in exceptional and extremely unusual hardship to a U.S. citizen or LPR parent, spouse, or child.

Non-LPR grants of cancellation of removal are limited to 4,000 per year.42

U nonimmigrant status may be granted to certain victims who help law enforcement agencies

investigate and prosecute domestic violence, sexual assault, human trafficking, and certain other

crimes.43 To qualify for U status, a foreign national must file a petition and establish that he/she

(1) suffered substantial physical or mental abuse as a result of having been a victim of qualifying

crimes that violated the laws of the United States or occurred in the United States; (2) possesses

information about the criminal activity involved as certified by a law enforcement or immigration

official; and (3) has been, is being, or is likely to be helpful in the investigation and prosecution

of the crime(s) by federal, state, or local law enforcement authorities. U status recipients, as well

as their immediate family members, can apply for LPR status after three years. The INA limits U

status to 10,000 principal applicants annually; there are no annual numerical limits on the number

of individuals with U status who can adjust to LPR status.44

36 INA §208; 8 U.S.C. §1158. For information on statutory bars on applying for asylum, see CRS Legal Sidebar

LSB10815, An Overview of the Statutory Bars to Asylum: Limitations on Applying for Asylum (Part One).

37 For more information about affirmative asylum, see CRS Report R48249, What Is Affirmative Asylum?.

38 For more information about defensive asylum, see CRS Report R47504, Asylum Process in Immigration Courts and

Selected Trends.

39 INA §209(b); 8 U.S.C. §1159(b).

40 For a detailed and complete list of categories of foreign nationals receiving LPR status, see DHS, Office of

Homeland Security Statistics, 2023 Yearbook of Immigration Statistics, Table 7.

41 INA §240A; 8 U.S.C. §1229b.

42 INA §240A(e); 8 U.S.C. §1229b(e).

43 INA §101(a)(15)(U); 8 U.S.C. §1101(a)(15)(U).

44 INA §214(p)(2); 8 U.S.C. §1184(p)(2). There is no limit for family members who derive U status or T status from

the principal applicant, such as spouses, children, or other eligible family members. For more information, see CRS

Report R47404, Immigration Relief for Noncitizen Crime Victims.

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T nonimmigrant status may be granted to victims of severe forms of human trafficking.45 To

qualify for T status, trafficking victims must (1) demonstrate that they are victims of a severe

form of trafficking in persons; (2) be physically present in the United States, its territories, or a

U.S. port of entry either because of such trafficking or because they will participate in related

investigations or prosecutions; (3) have complied with requests to assist law enforcement

investigating or prosecuting trafficking acts;46 and (4) be likely to suffer unusual and severe harm

upon removal. Such aliens must also be admissible to the United States or obtain a waiver of

inadmissibility (see the “Visa Issuance and Security” section). T status recipients may remain in

the United States for four years and apply for LPR status after three years. The INA limits T

status to 5,000 principal applicants annually and adjustment to LPR status by individuals with T

status to 5,000 principal aliens annually.47

Naturalization

Under the INA, eligible LPRs may become U.S. citizens through the naturalization process.48

With some exceptions,49 naturalization applicants must have resided continuously in the United

States as LPRs for five years (three years for the spouses of U.S. citizens50) and demonstrate good

moral character during the statutory period.

An individual may apply to naturalize by filing an application with USCIS and completing a

biometric-based background check. Applicants then undergo an interview with USCIS during

which they answer questions about their application and background and take English and civics

tests. Those whose applications are approved become U.S. citizens after taking the Oath of

Allegiance in a naturalization ceremony.

There are no numerical limits on naturalizations. In FY2024, USCIS naturalized 818,500 U.S.

citizens.51 In 2023, an estimated 25 million naturalized citizens resided in the United States,

comprising 52% of the estimated 47.8 million foreign-born U.S. residents.52 As of January 2024,

an estimated 8.7 million LPRs were potentially able to naturalize based on having met age and

residency requirements.53

A naturalized citizen may have his/her citizenship revoked on the basis that the citizenship was

procured illegally, by concealment of material fact, or by willful misrepresentation.54

45 INA §101(a)(15)(T); 8 U.S.C. §1101(a)(15)(T). For more information, see CRS Report R46584, Immigration Relief

for Victims of Trafficking and CRS Report R47404, Immigration Relief for Noncitizen Crime Victims.

46 Exceptions may be granted to individuals who are unable to cooperate with a request for assistance due to physical or

psychological trauma or because they are under age 18. INA §101(a)(15)(T)(i)(III); 8 U.S.C. §1101 (a)(15)(T)(i)(III).

47 INA §214(o)(2), 8 U.S.C. §1184(o)(2); INA §245(l)(4)(A), 8 U.S.C. §1255(l)(4)(A).

48 INA §316; 8 U.S.C. §1427. For more information, see CRS Report R43366, U.S. Naturalization Policy and CRS In

Focus IF12322, Naturalization: Policy Overview and Selected Trends.

49 The INA contains provisions for expedited naturalization through qualifying military service, INA §§328, 329; 8

U.S.C. §§1439, 1440. For more information, see CRS Report R48163, Foreign Nationals in the U.S. Armed Forces:

Immigration Issues.

50 INA §319; 8 U.S.C. §1429.

51 USCIS, “Naturalization Statistics,” https://www.uscis.gov/citizenship-resource-center/naturalization-statistics,

January 24, 2025.

52 U.S. Census Bureau, 2023 American Community Survey data, 1-year estimates.

53 Sarah Miller, Estimates of the Lawful Permanent Resident Population in the United States and the Subpopulation

Eligible to Naturalize: 2024 and Revised 2023, DHS Office of Homeland Security Statistics, September 2024.

54 INA §340(a); 8 U.S.C. §1451(a).

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Temporary Immigration

Nonimmigrants are foreign nationals admitted to the United States for a specified purpose and

temporary period, including tourists, diplomats, students, temporary workers, and exchange

visitors, among others.55 Each year, the United States admits millions of nonimmigrants. DOS

issues specific types of nonimmigrant visas within 24 major nonimmigrant visa categories.

Categories are often referred to by the letter and numeral denoting the related subsection within

INA Section 101(a)(15) (e.g., B-2 tourists, F-1 foreign students, H-2A temporary agricultural

workers).56 The INA and federal regulations set terms for nonimmigrant lengths of stay in the

United States, which typically include foreign residency requirements and often limit what aliens

are permitted to do while in the country (e.g., work, enroll in school).

Foreign nationals who apply for temporary admission must demonstrate, both to DOS consular

officers at the time they apply for a visa abroad, as well as to CBP officers when they apply for

admission upon arrival in the United States, that they are eligible for both nonimmigrant status

generally and the specific nonimmigrant status for which they are applying. In addition, because

the INA presumes that all aliens seeking admission to the United States are coming to live

permanently, nonimmigrant applicants must demonstrate that they intend to depart the United

States by the time their authorized period of stay expires (see the “Visa Issuance and Security”

section).57 Some nonimmigrants are permitted to work in the United States (e.g., temporary

workers, students pursuing optional practical training).

Some nonimmigrant categories have annual numerical limits; others do not.58 In FY2023, DOS

issued 10.4 million nonimmigrant visas, with the largest number of visa issuances to B-1 business

visitors and B-2 tourists (57%); border crossing card (BCC) holders (17%); H-2A, H-2B, and H1B temporary workers (7%); F-1 foreign students (4%); C-1/D transit/crew members (3%); and J1 cultural exchange visitors (3%).59

In addition to nonimmigrant visas, BCCs allow Mexican citizens who live in Mexico and are

admissible as B-1 business or B-2 tourist visitors to briefly enter certain regions of the United

States.60 In FY2023, DOS issued approximately 1.8 million border crossing cards to Mexican

nationals.61 The BCC may be used for multiple entries and is usually valid for 10 years. Current

regulations limit BCC holders to visits of up to 30 days within a zone of 25 miles along the

border in Texas and California, 55 miles along the New Mexico border, and 75 miles along the

Arizona border.62

55 INA §101(a)(15); 8 U.S.C. §1101(a)(15).

56 For more information, see CRS Report R45040, Immigration: Nonimmigrant (Temporary) Admissions to the United

States.

57 INA §214(b); 8 U.S.C. §1184(b). Many temporary visa holders eventually are able to adjust their status to LPR status

after they have been admitted to the United States as nonimmigrants. In FY2023, for example, of the 1,172,910 foreign

nationals who were granted LPR status, 564,660 (48%) were new arrivals from abroad and 608,260 (52%) adjusted

status from a nonimmigrant status while residing in the United States. Data to show the nonimmigrant categories that

foreign nationals adjust status from are unavailable. See DHS 2023 Yearbook of Immigration Statistics, Table 6.

58 For a list of nonimmigrant categories and annual numerical limits, see CRS Report R45938, Nonimmigrant and

Immigrant Visa Categories: Data Brief.

59 See CRS Report R45938, Nonimmigrant and Immigrant Visa Categories: Data Brief and DOS, Bureau of Consular

Affairs, Report of the Visa Office 2023.

60 8 C.F.R. §212.6

61 DOS, Bureau of Consular Affairs, Report of the Visa Office 2023, Table XVI.

62 8 C.F.R. §235.1.

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The Visa Waiver Program (VWP) allows citizens of 42 participating countries (or jurisdictions)—

which must meet a number of qualifying criteria—to enter the United States as temporary visitors

for business or pleasure without visas.63 In FY2023, roughly 15.4 million pleasure and 2 million

business visitors entered the United States using the VWP.64

Nonimmigrants must depart the United States before their authorized period of admission ends

unless they obtain an extension of stay or change of status that permits them to remain in the

country. On average, between 1% and 2% of nonimmigrant admissions result in an overstay each

year.65 Individuals who overstay are subject to removal from the United States (see the

“Immigration Enforcement” section).

Discretionary Permissions to Enter or Remain in the United States

The executive branch may exercise statutory or executive authority to allow certain noncitizens to

enter or remain in the United States. These noncitizens may include individuals who were not

legally admitted into the country or who may be subject to removal from the country. These

discretionary permissions include Temporary Protected Status (TPS), deferred enforced departure,

immigration parole, and Deferred Action for Childhood Arrivals (DACA). They are granted for a

temporary period by DHS and do not provide a dedicated pathway to permanent status. Other

categories that allow persons to remain in the United States regardless of immigration status,

including withholding of removal and deferred action, are described in later sections of this

report.

Temporary Protected Status

When extraordinary conditions such as civil unrest, violence, or natural disasters occur in foreign

countries, foreign nationals from those places who are present in the United States may not be

able to return home safely. The INA allows the DHS Secretary to designate countries for TPS for

periods of 6, 12, or 18 months at a time.66 Congress has also provided TPS legislatively. As of

September 2024, there were approximately 1.1 million individuals in the United States with

TPS.67 As of the cover date of this report, 17 countries were designated for TPS: Afghanistan,

Burma, Cameroon, El Salvador, Ethiopia, Haiti, Honduras, Lebanon, Nepal, Nicaragua, Somalia,

South Sudan, Sudan, Syria, Ukraine, Venezuela, and Yemen.

Nationals of designated countries already present in the United States may apply for TPS.

Individuals granted TPS are eligible for employment authorization, cannot be detained on the

basis of their immigration status, and are not subject to removal while they retain TPS. TPS does

not provide a recipient with a designated pathway to LPR status; however, a TPS recipient is not

barred from acquiring a lawful immigration status (e.g., asylum, nonimmigrant status, LPR

status) if he/she meets the requirements.

Applicants apply for TPS with USCIS according to deadlines set in the Federal Register notices

that announce each TPS designation or extension. These notices specify the dates by which

63 For more information, see CRS Report RL32221, Visa Waiver Program.

64 See DHS Office of Homeland Security Statistics, 2023 Yearbook of Immigration Statistics, Table 25.

65 For more information, see CRS Report R47848, Nonimmigrant Overstays: Overview and Policy Issues.

66 INA §244, 8 U.S.C. §1254a. For more information, see CRS Report RS20844, Temporary Protected Status and

Deferred Enforced Departure.

67 For more information, see CRS Report RS20844, Temporary Protected Status and Deferred Enforced Departure.

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individuals must have continuously resided in the United States in order to qualify. Foreign

nationals outside the United States are not eligible for TPS.

Deferred Enforced Departure

DED may be authorized by the President based on the executive branch’s independent

constitutional authority rather than any specific statutory authority. It provides a temporary,

discretionary, administrative stay of removal to foreign nationals from designated areas. The

Administration may use its discretion when applying DED to a particular area by balancing

foreign policy, humanitarian, and immigration concerns. DED grants are announced for set

periods of time at the President’s discretion and may be extended. As of the cover date of this

report, certain Palestinians, Lebanese, Liberians, and residents of Hong Kong living in the United

States maintain protection under DED. 68 Covered individuals may apply for work authorization

but they are not required to apply for DED; DED is triggered during removal proceedings.

Immigration Parole

The INA authorizes DHS, on a case-by-case basis, to parole an alien into the United States for

urgent humanitarian reasons or significant public benefit at its discretion.69 Foreign nationals may

request parole inside or outside the United States. Parole is granted for a specified period and

does not constitute formal admission to the United States. A parole grant generally does not

provide a dedicated path to LPR status.70 Persons granted parole (parolees) may obtain

employment authorization. Those granted parole must depart the United States when the parole

expires or, if eligible, be admitted in a lawful status. Parolees may also apply for re-parole.71

In recent years, the use of parole processes for specific populations (e.g., special processes set up

during the Biden Administration for nationals of Ukraine, Cuba, Haiti, Nicaragua, and Venezuela)

have been subject to debate. As of the cover date of this report, many of these processes have

been terminated or paused by the Trump Administration.72

Deferred Action for Childhood Arrivals

Under the DACA initiative, established by executive action in 2012, certain individuals without a

lawful immigration status who were brought to the United States as children and meet other

criteria have been granted deferred action for two years, subject to renewal. DACA eligibility is

based on requirements related to age, U.S. residence, education, and criminal history as

established in a June 15, 2012, DHS memorandum.73 Deferred action is “a type of prosecutorial

discretion that allows an individual to remain in the United States for a set period of time.”74

68 For more information, see CRS Report RS20844, Temporary Protected Status and Deferred Enforced Departure.

69 INA §212(d)(5); 8 U.S.C. §1182(d)(5).

70 Cubans are an exception because Congress established a special pathway to LPR status for Cuban parolees under the

Cuban Adjustment Act of 1966 (P.L. 89-732).

71 For more information, see CRS Report R46570, Immigration Parole.

72 See, for example, DHS, “Termination of Parole Processes for Cubans, Haitians, Nicaraguans, and Venezuelans,” 90

Federal Register 56, March 25, 2025. For more information on Biden Adminstration-era special parole processes, see

CRS Report R47654, Immigration Options for Immigration Parolees; for information on legal debates and changes

under the second Trump Administration, see CRS Legal Sidebar LSB11102, Humanitarian Parole Authority: A Legal

Overview and Recent Developments and CRS Legal Sidebar LSB11265, Recent White House Actions on Immigration.

73 For more information, see CRS Report R46764, Deferred Action for Childhood Arrivals (DACA): By the Numbers.

74 USCIS, “Glossary,” https://www.uscis.gov/tools/glossary.

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To qualify for DACA, an individual must have been under age 31 as of June 15, 2007 (the issue

date of the memorandum), physically present in the United States, entered the United States no

later than five years before the memorandum’s issue date, and have been continuously resident

since then. In addition, the individual must have been under age 16 at the time of initial entry. As

of the end of FY2024, there were 537,730 active DACA recipients.75

Like those covered by TPS, DED, and granted parole, DACA recipients can apply for

employment authorization but have no dedicated path to LPR status. DACA has been subject to

ongoing litigation challenging its legality but remains in effect as of the cover date of this

report.76 Currently, USCIS processes only DACA renewal applications and accompanying

applications for employment authorization; it does not process initial DACA requests from

individuals who have never had DACA.77

Immigration Enforcement

Immigration enforcement involves the identification, investigation, apprehension, detention,

prosecution, and removal (deportation) of foreign nationals who are inadmissible and/or become

removable. Immigration enforcement encompasses enforcement of the INA’s civil provisions

(e.g., violations of admission requirements) as well as its criminal provisions (e.g., improper

entry, marriage fraud, alien smuggling).

Two DHS agencies are primarily responsible for immigration enforcement. CBP is responsible

for border security where foreign nationals enter at U.S. land, air, and sea ports of entry (POEs)

and along U.S. borders between POEs.78 ICE is responsible for enforcing immigration laws in the

U.S. interior, including worksite enforcement; ICE also oversees immigration detention. Both

agencies effectuate removals and returns of foreign nationals.

Border Enforcement at Ports of Entry

Foreign nationals may arrive in the United States at 328 land, air, and sea POEs, which are

managed by CBP’s Office of Field Operations (OFO). OFO had 26,030 officers on staff at the end

of FY2023.79 OFO has the dual responsibility for facilitating the flow of lawful travel and trade

while providing security at POEs against inadmissible persons and unlawful goods (e.g., unlawful

firearms, imports, narcotics).

This includes screening at multiple points in the immigration process. DHS uses screening tools

to distinguish low-risk travelers who may be eligible for expedited admissions processing from

lesser-known, higher-risk travelers who are usually subject to more extensive secondary

75 At that time, DACA recipients’ average age was 30.6. USCIS, “Count of Active DACA Recipients as of September

30, 2024,” available from USCIS, “Immigration and Citizenship Data,” https://www.uscis.gov/tools/reports-andstudies/immigration-and-citizenship-data.

76 For more information, see CRS Legal Sidebar LSB10625, The Legality of DACA: Recent Litigation Developments.

77 USCIS, “Consideration of Deferred Action for Childhood Arrivals,” https://www.uscis.gov/DACA, January 24,

2025.

78 This report does not cover immigration enforcement along U.S. coastal waters, which the U.S. Coast Guard, Alien

Migrant Interdiction Operations oversees. For more information, see DHS, Office of Homeland Security Statistics, U.S.

Coast Guard Maritime Response Activities Fiscal Year 2020-2023.

79 U.S. Government Accountability Office (GAO), U.S. Customs and Border Protection: Efforts to Improve

Recruitment, Hiring, and Retention of Law Enforcement Personnel, GAO-24-107029, September 2024.

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inspections.80 Possession of a visa by a foreign national does not guarantee U.S. admission; a

CBP officer may find the individual inadmissible.81

DHS is responsible for implementing an automated entry-exit system at POEs, a task Congress

mandated in 1996.82 Congress added a biometric requirement in 2001.83 While CBP collects a

portion of the requisite biographic and biometric data from noncitizens at various stages of their

entry to and exit from the United States, the implementation of a fully automated biometric

system has proven to be challenging.84 DHS has fully implemented the biometric entry system at

all U.S. ports of entry. Reportedly, the biometric exit system currently captures information on

about 80% of foreign nationals aged 14-79 departing the United States via participating

commercial air carriers. The biographic and biometric exit system is at various stages of

completion for air, sea, and land POEs.85

Border Enforcement Between Ports of Entry

Border enforcement between POEs protects against unauthorized land border entry into the

United States. CBP’s U.S. Border Patrol (USBP) works to prevent the unlawful entry of persons

and contraband into the country between POEs at U.S. southern and northern land borders

(approximately 6,000 miles) and coastal borders (2,000 miles). USBP’s objectives include

predicting, detecting, and identifying threats to national security; deploying personnel, equipment,

and intelligence to secure the border; and classifying, prioritizing, and mitigating known threats.86

DHS reported in 2021 that since receiving authorization from Congress in 1996, approximately

701 miles of primary barriers have been built along the U.S.-Mexico border, which spans nearly

2,000 miles.87 The second Trump Administration has announced plans to construct additional

miles of border wall.88 Tactical infrastructure also includes roads, gates, bridges, and lighting

designed to support border enforcement and disrupt and impede illicit activity. Surveillance

technology assists CBP in the detection, identification, and apprehension of individuals illegally

entering the United States between POEs. Ground technology includes sensors, cameras, and

radar tailored to fit specific terrain and population densities. Manned and unmanned aerial and

80 For more information, see CRS Report R46783, Trusted Traveler Programs.

81 INA §221(h); 8 U.S.C. §1201(h).

82 This requirement was enacted in the Illegal Immigration Reform and Immigrant Responsibility Act of 1996 (IIRIRA,

P.L. 104-208), Section 110.

83 Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism

Act (USA PATRIOT Act, P.L. 107-56), Section 414.

84 For more information, see CRS Report R47541, Immigration: The U.S. Entry-Exit System.

85 For more information, see CRS Report R47541, Immigration: The U.S. Entry-Exit System.

86 USBP, 2024-2028 Strategy, March 2024.

87 CBP and U.S. Army Corps of Engineers, “Border Wall Status – January 8, 2021.” For more information, see CRS

Report R45888, DHS Border Barrier Funding Through FY2021 and U.S. Government Accountability Office,

Southwest Border Security: Additional Actions Needed to Better Assess Fencing’s Contributions to and Operations and

Provide Guidance for Identifying Capability Gaps, GAO-17-331, February 2017. During the Biden Administration,

wall construction was largely halted; however, some projects were approved to complete gaps in existing border

barriers. See DHS, “DHS to Address Life, Safety, and Operational Requirements in the U.S. Border Patrol’s Yuma

Sector,” July 28, 2022, and CRS Report R47979, DHS Border Barrier Funding Developments: FY2021-FY2024.

88 For example, in March 2025 CBP announced plans to complete seven miles of new border wall in the USBP’s Rio

Grande Valley Sector with FY2021 funds. CBP, “CBP awards first border wall contract of President Trump’s second

term,” March 15, 2025.

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marine surveillance vessels patrol regions inaccessible by motor vehicle.89 At the end of FY2023,

according to CBP data, there were approximately 19,000 U.S. Border Patrol agents on staff.90

In recent years, CBP has had record-high levels of enforcement encounters at the Southwest

border. Encounters have reflected a diverse array of national origins and a relatively high rate of

children and families, many seeking asylum.91 Border enforcement encounters began to slow at

the end of FY2024.92

Although CBP is primarily responsible for border enforcement, other agencies also play a role;

including ICE, which provides transportation support and detention space and carries out

removals; and ORR, which is responsible for the care and custody of unaccompanied alien

children apprehended at the border.93

Interior Immigration Enforcement

ICE’s Enforcement and Removal Operations (ERO) is responsible for interior immigration

enforcement, which involves the identification, apprehension, detention, supervision,

transportation, and removal of aliens who violate U.S. immigration laws. These may include

aliens who entered the United States without inspection, overstayed a nonimmigrant visa, or

otherwise violated the terms of a lawful admission. DHS has prosecutorial discretion to set civil

immigration enforcement priorities, which may vary over time and across Administrations.94

ERO operates programs to identify criminal and other removable aliens, including the Criminal

Alien Program (CAP),95 which “identifies, locates and arrests noncitizens in the custody of other

law enforcement agencies, as well as those noncitizens released from other law enforcement

agencies who were arrested for criminal activity.”96 CAP includes a data sharing infrastructure, or

interoperability, between DHS and DOJ that screens for both immigration and criminal violations

when individuals are booked into prisons or jails that participate in the program. To pursue known

at-large criminal aliens and fugitive aliens outside of controlled settings (i.e., administrative

offices or custodial settings), ICE uses the National Fugitive Operations Program. ICE’s Section

89 See archived CRS Insight IN11040, Border Security Between Ports of Entry: Homeland Security Issues in the 116th

Congress.

90 GAO, U.S. Customs and Border Protection: Efforts to Improve Recruitment, Hiring, and Retention of Law

Enforcement Personnel, GAO-24-107029, September 2024.

91 Among all CBP encounters at the Southwest border, the proportion with children and family units was 41% in

FY2025 through February, 43% in FY2024, 39% in FY2023, and 30% in FY2022. CBP, “Nationwide Encounters,”

https://www.cbp.gov/newsroom/stats/nationwide-encounters. See also Figure 2 in archived CRS Report R47556, U.S.

Border Patrol Encounters at the Southwest Border: Fact Sheet.

92 CBP, “Nationwide Encounters,” https://www.cbp.gov/newsroom/stats/nationwide-encounters.

Unaccompanied alien children are children who are under age 18, lack lawful immigration status in the United

States, and do not have a parent or legal guardian in the United States, or a parent or legal guardian who is available to

provide care and physical custody. For more information, see CRS Report R43599, Unaccompanied Alien Children: An

Overview.

94 For more information, see CRS Legal Sidebar LSB10578, The Biden Administration’s Immigration Enforcement

Priorities: Background and Legal Considerations and CRS Legal Sidebar LSB10362, Immigration Arrests in the

Interior of the United States: A Primer.

95 The program has also been referred to as the Criminal Apprehension Program. An ICE website, https://www.ice.gov/

identify-and-arrest/criminal-alien-program, updated January 27, 2025, refers to this program as the Criminal Alien

Program; its FY2024 annual report uses Criminal Apprehension Program; ICE, ICE Annual Report FY2024, p. 93.

96 ICE, ICE Annual Report FY2024, p. 15.

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287(g) program allows DHS to delegate certain immigration enforcement functions to specially

trained state and local law enforcement officers, under federal supervision.97

ICE’s interior enforcement responsibility includes worksite enforcement, which is conducted by

ICE’s Homeland Security Investigations (HSI) directorate. The INA prohibits an employer from

knowingly hiring, recruiting or referring for a fee, or continuing to employ an alien who lacks

work authorization.98 Employers who violate prohibitions on unauthorized employment may be

subject to civil monetary penalties and/or criminal penalties.

Detention and Case Management

ICE’s ERO is responsible for the nation’s civil immigration detention system. The INA

authorizes—and in some cases requires—DHS to detain foreign nationals who are subject to

removal from the United States. Detention statutes are multifaceted and depend on several

factors, such as whether the individual is seeking admission or has been lawfully admitted into

the country, has engaged in certain proscribed conduct, and has been issued a final order of

removal. Four INA provisions provide a framework for immigration detention:

•

INA Section 236(a) generally authorizes the detention of aliens pending a

decision on whether the alien is to be removed from the United States and

permits those who are not subject to mandatory detention to be released on bond

or their own recognizance;

INA Section 236(c) generally requires the detention of aliens who are removable

because of specified criminal activity or terrorism-related grounds;

INA Section 235(b) generally requires the detention of applicants for admission

who appear subject to removal, including aliens arriving at a POE and certain

other aliens who have not been admitted or paroled into the United States; and

INA Section 241(a) generally requires an alien subject to a final order of removal

to be held during the 90-day period when the alien’s removal is effectuated. DHS

may detain an alien beyond 90 days if the agency cannot effectuate removal and

the alien falls within certain categories.99

In FY2024, apprehended aliens were held in 129 ERO detention facilities.100 That year, ERO

primarily detained aliens apprehended by CBP at the Southwest border and transferred to ICE

custody, and aliens with criminal histories apprehended by ERO in the U.S. interior. ICE detained

37,684 persons at the end of FY2024.101 Detention capacity is controlled largely through funding

made available in congressional appropriations. Because detention capacity is limited, ICE may

97 For background information, see CRS In Focus IF11898, The 287(g) Program: State and Local Immigration

Enforcement.

98 INA §274A; 8 U.S.C. §1324a.

99 This material is adapted from CRS In Focus IF11343, The Law of Immigration Detention: A Brief Introduction. For

more information on standards and criteria for making detention decisions, see also CRS Report R45915, Immigration

Detention: A Legal Overview.

100 This number includes facilities owned and operated by ICE, a state or local entity, or a contractor and excludes

“hold rooms, hospital, and juvenile facilities.” ICE, Annual Report Fiscal Year 2024, p. 22. See also ICE, “Detention

Management,” https://www.ice.gov/detain/detention-management.

101 ICE, Annual Report Fiscal Year 2024, p. 23.

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prioritize detaining certain populations (e.g., those subject to mandatory detention under the INA,

those considered public safety or national security threats, and flight risks).102

ICE also manages a non-detained docket of individuals released from custody who are awaiting

removal proceedings or subject to final orders of removal. At the end of FY2024, there were 7.6

million people on the non-detained docket, a nearly 25% increase from FY2023.103 Some

individuals on the non-detained docket are supervised under ERO’s Alternatives to Detention

(ATD) program. This program allows ICE to monitor certain aliens subject to removal who have

been released into the United States, using technology (e.g., mobile applications, ankle monitors)

and case management options (e.g., home visits, virtual check-ins).104 ICE reported 179,000 ATD

participants as of the end of FY2024.105

Removal Processes

Removing foreign nationals who violate U.S. immigration and other laws is central to

immigration enforcement, and the INA provides broad authority to DHS and DOJ to remove

certain foreign nationals from the country. These persons include unauthorized aliens as well as

lawfully present aliens who commit certain acts that make them removable. Any foreign national

found to be inadmissible (either before or after U.S. entry; see the “Visa Issuance and Security”

section for information on grounds of inadmissibility) or deportable under grounds specified in

the INA may be ordered removed.

Grounds of deportability specified in INA Section 237(a) include the following:

•

being inadmissible at the time of entry106 or violating one’s immigration status;

committing certain criminal offenses, including crimes of “moral turpitude,”

aggravated felonies, alien smuggling, and high-speed flight from an immigration

checkpoint;107

failing to register with DHS (if required) or committing document fraud;

being a security risk (including violating any law relating to espionage, engaging

in criminal activity that endangers public safety, partaking in terrorist activities,

or assisting in Nazi persecution or genocide);

becoming a public charge within five years of entry; or

voting unlawfully.

Absent other factors, unlawful presence in the United States is a civil violation, not a criminal

offense, and removal and its associated administrative processes are civil proceedings. The INA

provides for multiple types of removal processes. DHS may commence formal removal

proceedings by issuing a foreign national a Notice to Appear charging document and filing it with

102 See ICE, Annual Report Fiscal Year 2024, p. 22 and CRS Report R45915, Immigration Detention: A Legal

Overview.

103 ICE, Annual Report Fiscal Year 2024, p. 27.

104 See ICE, “Alternatives to Detention,” https://www.ice.gov/features/atd.

105 ICE, Annual Report Fiscal Year 2024, p. 29.

106 Grounds of inadmissibility are outlined in INA Section 212; 8 U.S.C. §1182. If individuals are removed because

they were inadmissible at the time of entry, they are removed under INA Section 212, not INA Section 237. For more

information, see CRS In Focus IF12662, Immigration: Grounds of Inadmissibility.

107 Crimes of moral turpitude are determined by case law. For more information, see CRS Report R45151, Immigration

Consequences of Criminal Activity.

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an immigration court within DOJ’s EOIR.108 Formal removal proceedings typically consist of

multiple hearings before an EOIR immigration judge.109 At the conclusion of proceedings, an

immigration judge determines whether a foreign national is removable as charged. The

immigration judge may grant certain forms of relief or protection (e.g., asylum, cancellation of

removal) for which the alien has applied.

Under streamlined removal procedures, including expedited removal and reinstatement of

removal (i.e., when DHS reinstates a removal order for an individual previously removed),110

opportunities for relief and review are generally limited. Expedited removal allows DHS to

remove an alien without a formal hearing under certain statutory conditions.111 However,

individuals subject to expedited removal may have an opportunity to pursue applications for

asylum and other forms of protection from removal.112

Aliens with a final removal order must generally be removed by DHS within 90 days, during

which time they may be detained.113 Individuals with a final order of removal may be repatriated

by DHS to their country of citizenship or to a third country. This process requires cooperation

from the country designated for removal, which must confirm the individual’s nationality, issue

travel documents, and accept their physical return. Under a 2001 Supreme Court decision

(Zadvydas v. Davis), detained aliens subject to removal orders but for whom there is “no

significant likelihood of removal in the reasonably foreseeable future” must be released into the

United States after six months, with limited exceptions.114 DHS considers countries that refuse or

delay the repatriation of their citizens to be recalcitrant or uncooperative.115 Foreign nationals

who have been removed generally are ineligible to return to the United States for a minimum of

five years.116

In other instances, foreign nationals may be repatriated through returns, including voluntary

returns, voluntary departure, and withdrawal of petition for admission. Returns require foreign

nationals to leave the United States promptly but exempt them from certain penalties associated

with removal.

Defenses Against Removal

INA provisions permit certain removable aliens to remain in the United States, either permanently

or temporarily. Some of these options have already been described in previous sections of this

report. Options that provide permanent relief by conferring or leading to LPR status include

cancellation of removal (see the “Other Pathways to LPR Status” section) and defensive asylum

108 INA §239; 8 U.S.C. §1229. For more information on immigration courts, see CRS Report R47077, U.S.

Immigration Courts and the Pending Cases Backlog.

109 INA §240; 8 U.S.C. §1229a. For more information about formal removal proceedings, see CRS In Focus IF11536,

Formal Removal Proceedings: An Introduction.

110 For more information about reinstatement of removal, see CRS In Focus IF11736, Reinstatement of Removal

Orders: An Introduction.

111 INA §235(b)(1); 8 U.S.C. §1225. For more information about expedited removal, see CRS In Focus IF11357,

Expedited Removal of Aliens: An Introduction.

112 For more information, see CRS Report R48078, Credible Fear and Defensive Asylum Processes: Frequently Asked

Questions.

113 INA §241(a); 8 U.S.C. §1231(a).

114 For more information, see CRS Report R45915, Immigration Detention: A Legal Overview.

115 For more information, see CRS In Focus IF11025, Immigration: “Recalcitrant” Countries and the Use of Visa

Sanctions to Encourage Cooperation with Alien Removals.

116 INA §212(a)(9)(A); 8 U.S.C. §1182(a)(9)(A). For more information, see CRS In Focus IF12484, The Statutory Bars

to Reentry into the United States.

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Primer on U.S. Immigration Policy

applied for during removal proceedings (see the “Refugees and Asylees” section).117 Individuals

may also obtain temporary protection from removal through TPS, DED, and DACA (see the

“Discretionary Permissions to Enter or Remain in the United States” section). Additional options

that provide temporary relief from removal include withholding of removal, Convention Against

Torture (CAT) protection, and deferred action.

Withholding of removal may be granted to foreign nationals who can demonstrate that it is more

likely than not that if removed to their home country they would be persecuted on account of their

race, religion, nationality, membership in a particular social group, or political opinion. Like

asylum, withholding of removal protects people from removal to a country where they fear

persecution. Withholding of removal is granted by an EOIR immigration judge. Unlike asylum,

an immigration judge has no discretion and must grant withholding of removal to applicants who

meet the requirements.118 In addition, to be granted withholding of removal, applicants must

prove that it is “more likely than not” that they will be persecuted based on a protected ground.119

CAT protection may be granted by an immigration judge to individuals who fear torture in their

home country. To qualify, applicants must demonstrate that it is more likely than not that they will

be tortured directly by or with the acquiescence of the government of their country of origin.120

Withholding of removal and CAT protection provide no path to LPR status and allow for possible

removal to a third country.121

Deferred action is a form of prosecutorial discretion exercised by DHS that temporarily defers

removal against a covered individual.122 Examples of deferred action may include DHS

terminating removal proceedings, declining to initiate removal proceedings, or declining to

execute a final order of removal. DACA is one type of deferred action (see the “Deferred Action

for Childhood Arrivals” section). DHS has also implemented policies to provide deferred action

to workers cooperating in employment and labor standards investigations, certain relatives of

U.S. servicemembers and veterans, and crime victims awaiting adjudication of a petition for U

nonimmigrant status.123

117 If an individual is subject to removal but has not been placed in removal proceedings, they may apply for

affirmative asylum.

118 For more information, see CRS Report R48078, Credible Fear and Defensive Asylum Processes: Frequently Asked

Questions.

119 INA §241(b)(3)(A); 8 U.S.C. §1231(b)(3)(A), INS v. Stevic, 467 U.S. 407, 424, 429 ̶ 30 (1984) (explaining that an

application for withholding of removal must “be supported by evidence establishing that it is more likely than not that

the alien would be subject to persecution on one of the specified grounds.”). For more information, see CRS Report

R48078, Credible Fear and Defensive Asylum Processes: Frequently Asked Questions.

120 See archived CRS Report RL32276, The U.N. Convention Against Torture: Overview of U.S. Implementation Policy

Concerning the Removal of Aliens (available to congressional clients upon request to CRS).

121 For more information, see “Asylum and Related Forms of Relief” in CRS Report R48078, Credible Fear and

Defensive Asylum Processes: Frequently Asked Questions.

122 According to DHS, “Although deferred action does not confer lawful status or excuse any past or future periods of

unlawful presence, a noncitizen granted deferred action is considered lawfully present in the United States for certain

limited purposes, while the deferred action is in effect.” DHS, “DHS Support of the Enforcement of Labor and

Employment Laws,” January 6, 2025.

123 See USCIS, “DHS Support of the Enforcement of Labor and Employment Laws,” last updated January 24, 2025.

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Primer on U.S. Immigration Policy

Author Information

Holly Straut-Eppsteiner

Analyst in Immigration Policy

Disclaimer

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R45020 · VERSION 12 · UPDATED

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.