Warren -- U.S. County in Ohio Population (2000): 158383 Housing Units (2000): 58692 Land area (2000): 399.626742 sq. miles (1035.028467 sq. km) Water area (2000): 7.512158 sq. miles (19.456400 sq. km) Total area (2000): 407.138900 sq. miles (1054.484867 sq. km) Located within: Ohio (OH), FIPS 39 Location: 39.440152 N, 84.221759 W Headwords: Warren Warren, OH Warren County Warren County, OH