Miss. Code § 51-35-305
Flood and drainage control districts may now or hereafter be organized in this state under the provisions of this article, in the manner hereinafter provided, whenever any part of such district lies wholly or partially in or adjacent to any part of a municipality having a population of ten thousand (10,000) or more inhabitants at the time of the filing of the petition to create such district. For the purposes of determining population of any municipality, the last completed census prior to the filing of such petition shall be presumed to be the population of such municipality at the time of the filing of such petition. Each flood and drainage control district shall be an agency of the state and a body politic and corporate, and may be composed of one or more entire municipalities or a part or parts thereof, one or more entire counties or a part or parts thereof, or any combination of counties and municipalities or a part or parts thereof.
Miss. Code § 51-35-305