There are 3 US Post Offices in Wayne County serving a total of 16,978 residents equating to 5,659 residents per post office. It's estimated that approximately 27,099 packages are handled across the 3 county post offices annually. Wayne County is a county located in the U.S. state of Mississippi. As of the 2010 census, the population was 20,747. Its county seat is Waynesboro. The county is named for General Anthony Wayne."