Clark -- U.S. County in Washington Population (2000): 345238 Housing Units (2000): 134030 Land area (2000): 628.221812 sq. miles (1627.086954 sq. km) Water area (2000): 27.993396 sq. miles (72.502560 sq. km) Total area (2000): 656.215208 sq. miles (1699.589514 sq. km) Located within: Washington (WA), FIPS 53 Location: 45.692187 N, 122.547831 W Headwords: Clark Clark, WA Clark County Clark County, WA