Montgomery -- U.S. County in Ohio Population (2000): 559062 Housing Units (2000): 248443 Land area (2000): 461.675942 sq. miles (1195.735149 sq. km) Water area (2000): 2.668011 sq. miles (6.910116 sq. km) Total area (2000): 464.343953 sq. miles (1202.645265 sq. km) Located within: Ohio (OH), FIPS 39 Location: 39.750258 N, 84.218590 W Headwords: Montgomery Montgomery, OH Montgomery County Montgomery County, OH