Champaign -- U.S. County in Ohio Population (2000): 38890 Housing Units (2000): 15890 Land area (2000): 428.559933 sq. miles (1109.965084 sq. km) Water area (2000): 1.146319 sq. miles (2.968952 sq. km) Total area (2000): 429.706252 sq. miles (1112.934036 sq. km) Located within: Ohio (OH), FIPS 39 Location: 40.127656 N, 83.770972 W Headwords: Champaign Champaign, OH Champaign County Champaign County, OH