Marion -- U.S. County in Missouri Population (2000): 28289 Housing Units (2000): 12443 Land area (2000): 438.074614 sq. miles (1134.607993 sq. km) Water area (2000): 5.972228 sq. miles (15.468000 sq. km) Total area (2000): 444.046842 sq. miles (1150.075993 sq. km) Located within: Missouri (MO), FIPS 29 Location: 39.770045 N, 91.507631 W Headwords: Marion Marion, MO Marion County Marion County, MO