Hardin County, OH adjoins Logan near Kenton metropolitan centre yielding a 2020 estimated population standing at 31,439 making it the 28th highest populous county located within Ohio overall. Its county seat is Kenton with other cities include Ada & Forest-Kenton itself equates out to Hardin's largestcity aside from noted country seat. This area had been formed from Logan and Union Counties back in 1820 when local citizens petitioned for new administrative boundaries - posthumously named after Colonel John Hardin commanding era during James Monroe .