Miss. Code § 65-19-55
When the funds raised in any separate road district by bond issue have been expended and the contracts for road construction have been completed under the methods of building roads authorized by law, it shall be lawful for the road commissioners of any such road district, by and with the consent of the board of supervisors, to turn over to the county in which such road district is situated the roads so constructed. It shall then become the duty of the board of supervisors of such county to maintain and keep up such roads in place and stead of and in the same manner as the road commissioners of such district, and manage in place of said commissioners all of the fiscal affairs of said road district. The funds of each district shall be kept separate and applied to the district in which it was collected.
Miss. Code § 65-19-55