Sponsored Topics. Waynesboro is a city in and the county seat of Wayne County, Tennessee, United States. The population was 2,449 at the 2010 census. Waynesboro is located at 35°19′14″N 87°45′25″W / 35.32056°N 87.75694°W / 35.32056; -87.75694 (35.320546, -87.756984).