Union -- U.S. County in Arkansas Population (2000): 45629 Housing Units (2000): 20676 Land area (2000): 1038.902505 sq. miles (2690.745020 sq. km) Water area (2000): 16.367899 sq. miles (42.392663 sq. km) Total area (2000): 1055.270404 sq. miles (2733.137683 sq. km) Located within: Arkansas (AR), FIPS 05 Location: 33.207179 N, 92.612793 W Headwords: Union Union, AR Union County Union County, AR