Marshall -- U.S. County in Oklahoma Population (2000): 13184 Housing Units (2000): 8517 Land area (2000): 371.106393 sq. miles (961.161105 sq. km) Water area (2000): 55.840572 sq. miles (144.626411 sq. km) Total area (2000): 426.946965 sq. miles (1105.787516 sq. km) Located within: Oklahoma (OK), FIPS 40 Location: 34.012197 N, 96.730337 W Headwords: Marshall Marshall, OK Marshall County Marshall County, OK