Hardin County is a county located in the U.S. state of Ohio. As of the 2010 census, the population was 32,058. Its county seat is Kenton. The county was created in 1820 and later organized in 1833. It is named for John Hardin, an officer in the American Revolution.GeographyAccording to the U.S. Census Bureau, the county has a total area of, of which is land and (0.1%) is water.Adjacent countiesHancock County (north)Wyandot County (northeast)Marion County (east)Union County (southeast)Logan County (south)Auglaize County (southwest)Allen County (northwest)