Union -- U.S. County in Ohio Population (2000): 40909 Housing Units (2000): 15217 Land area (2000): 436.651495 sq. miles (1130.922131 sq. km) Water area (2000): 0.325673 sq. miles (0.843490 sq. km) Total area (2000): 436.977168 sq. miles (1131.765621 sq. km) Located within: Ohio (OH), FIPS 39 Location: 40.271860 N, 83.366607 W Headwords: Union Union, OH Union County Union County, OH