Kelso, WA -- U.S. city in Washington Population (2000): 11895 Housing Units (2000): 5067 Land area (2000): 8.082923 sq. miles (20.934673 sq. km) Water area (2000): 0.286484 sq. miles (0.741989 sq. km) Total area (2000): 8.369407 sq. miles (21.676662 sq. km) FIPS code: 35065 Located within: Washington (WA), FIPS 53 Location: 46.142033 N, 122.906027 W ZIP Codes (1990): 98626 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Kelso, WA Kelso