Washington -- U.S. County in Idaho Population (2000): 9977 Housing Units (2000): 4138 Land area (2000): 1456.318512 sq. miles (3771.847470 sq. km) Water area (2000): 17.225268 sq. miles (44.613238 sq. km) Total area (2000): 1473.543780 sq. miles (3816.460708 sq. km) Located within: Idaho (ID), FIPS 16 Location: 44.392256 N, 116.851251 W Headwords: Washington Washington, ID Washington County Washington County, ID