Jefferson -- U.S. County in Arkansas Population (2000): 84278 Housing Units (2000): 34350 Land area (2000): 884.815306 sq. miles (2291.661025 sq. km) Water area (2000): 28.881094 sq. miles (74.801688 sq. km) Total area (2000): 913.696400 sq. miles (2366.462713 sq. km) Located within: Arkansas (AR), FIPS 05 Location: 34.243795 N, 91.987152 W Headwords: Jefferson Jefferson, AR Jefferson County Jefferson County, AR