Miss. Code Ann. § 21-3-11: Miss. Code Ann. § 21-3-11

If any person elected as an alderman from a particular ward shall remove his residence from said ward, his office shall automatically be vacated, and if the mayor or any alderman elected from the municipality at large shall remove his residence from such municipality, the office shall likewise automatically be vacated. The vacancy shall be declared by the mayor and board of aldermen in the case of an alderman and by the board of aldermen in the case of a mayor, and such vacancy shall be filled in the manner prescribed by law.