Atchison -- U.S. County in Missouri Population (2000): 6430 Housing Units (2000): 3103 Land area (2000): 544.717621 sq. miles (1410.812102 sq. km) Water area (2000): 2.643486 sq. miles (6.846598 sq. km) Total area (2000): 547.361107 sq. miles (1417.658700 sq. km) Located within: Missouri (MO), FIPS 29 Location: 40.424242 N, 95.449856 W Headwords: Atchison Atchison, MO Atchison County Atchison County, MO