Clark County, Ohio

Clark County is a county in the U.S. state of Ohio. As of the 2010 census, the population was 138,333. Its county seat is Springfield. The county was created on March 1, 1818, and was named for General George Rogers Clark, a hero of the American Revolution.Clark County comprises the Springfield, OH Metropolitan Statistical Area, which is also included in the Dayton-Springfield-Sidney-OH Combined Statistical Area.GeographyAccording to the U.S. Census Bureau, the county has a total area of, of which is land and (1.3%) is water. It is the third-smallest county in Ohio by total area.Adjacent countiesChampaign County (north)Madison County (east)Greene County (south)Montgomery County (southwest)Miami County (west)