Sioux -- U.S. County in Iowa Population (2000): 31589 Housing Units (2000): 11260 Land area (2000): 767.883314 sq. miles (1988.808569 sq. km) Water area (2000): 0.699272 sq. miles (1.811107 sq. km) Total area (2000): 768.582586 sq. miles (1990.619676 sq. km) Located within: Iowa (IA), FIPS 19 Location: 43.075135 N, 96.182305 W Headwords: Sioux Sioux, IA Sioux County Sioux County, IA