Decatur is a town in Newton County, Mississippi, United States. The population was 1,426 at the 2000 census. It is the county seat of Newton County. This town is named after war hero Stephen Decatur, Jr.
Decatur is located at 32°26′22″N 89°6′43″W / 32.43944°N 89.11194°W / 32.43944; -89.11194 (32.439557, -89.112047).
According to the United States Census Bureau, the town has a total area of 1.0 square miles (2.7 km²), all of it land.