There are 3 US Post Offices in Amite County serving a total of 10,605 residents equating to 3,535 residents per post office. It's estimated that approximately 16,927 packages are handled across the 3 county post offices annually. Amite County /\u02c8e\u026a.m\u025bt/ is a county located in the state of Mississippi on its southern border with Louisiana. As of the 2010 census, the population was 13,131. Its county seat is Liberty. The county is named after the Amite River which runs through the county. The name is derived from the French amiti\u00e9, meaning \"friendship.\" Amite County is part of the McComb, MS Micropolitan Statistical Area."