Ottawa -- U.S. County in Ohio Population (2000): 40985 Housing Units (2000): 25532 Land area (2000): 254.953085 sq. miles (660.325431 sq. km) Water area (2000): 330.167727 sq. miles (855.130451 sq. km) Total area (2000): 585.120812 sq. miles (1515.455882 sq. km) Located within: Ohio (OH), FIPS 39 Location: 41.542200 N, 83.040528 W Headwords: Ottawa Ottawa, OH Ottawa County Ottawa County, OH