Decatur -- U.S. County in Tennessee Population (2000): 11731 Housing Units (2000): 6448 Land area (2000): 333.895541 sq. miles (864.785444 sq. km) Water area (2000): 11.014800 sq. miles (28.528201 sq. km) Total area (2000): 344.910341 sq. miles (893.313645 sq. km) Located within: Tennessee (TN), FIPS 47 Location: 35.615241 N, 88.116253 W Headwords: Decatur Decatur, TN Decatur County Decatur County, TN