Gilliam -- U.S. County in Oregon Population (2000): 1915 Housing Units (2000): 1043 Land area (2000): 1204.067807 sq. miles (3118.521172 sq. km) Water area (2000): 18.774428 sq. miles (48.625543 sq. km) Total area (2000): 1222.842235 sq. miles (3167.146715 sq. km) Located within: Oregon (OR), FIPS 41 Location: 45.314871 N, 120.152997 W Headwords: Gilliam Gilliam, OR Gilliam County Gilliam County, OR