Mississippi Code Title 37. Education § 37-7-723

In any county in which there exists a special municipal separate school district which embraces and includes the entire county, the county board of education of such county shall be forthwith discontinued and abolished. All of the duties provided by law which would otherwise devolve upon the county board of education of such county shall be performed and discharged by the board of trustees of the special municipal separate school district which for such purpose, shall have and be vested with all power, authority and duties now conferred by law upon the county board of education.