Jackson -- U.S. County in Arkansas Population (2000): 18418 Housing Units (2000): 7956 Land area (2000): 633.523674 sq. miles (1640.818713 sq. km) Water area (2000): 7.922670 sq. miles (20.519620 sq. km) Total area (2000): 641.446344 sq. miles (1661.338333 sq. km) Located within: Arkansas (AR), FIPS 05 Location: 35.613258 N, 91.227582 W Headwords: Jackson Jackson, AR Jackson County Jackson County, AR