Miss. Code § 65-7-79
The board of supervisors of any county in which a main highway in said county runs through several municipalities in said county, and lies partly within said municipalities and partly without, may join in and co-operate with the said municipalities in the joint construction, improvement, and maintenance of said highway, and out of the county road and bridge fund may pay a proportionate part of the cost of such construction, improvement, and maintenance, the municipalities also paying their proportionate parts. The board of supervisors may distribute its pro rata part of such cost over a period of not exceeding five annual payments and may direct its president to execute the notes of the county for said annual payments, to draw interest at a rate not exceeding six percent (6%) per annum.
Miss. Code § 65-7-79