Miss. Code Ann. § 65-1-39

The State Highway Commission is hereby authorized and empowered to take over, assume jurisdiction of, maintain, repair, and improve the public highways under the jurisdiction of the department of highways of the State of Louisiana on Australia Island, and to enter into such agreements with the department of highways of the State of Louisiana as the said State Highway Commission shall deem necessary, proper, and advisable, provided that the State Highway Commission of Mississippi is reimbursed for the expenditures incurred in the maintenance, repair, and improvement of said roads.

The powers conferred by this section are supplementary to the powers of said commission now provided by law and are not intended in any wise to conflict with the same.