Adams County, OH neighbors Brown near West Union metropolitan centre thus granting a 2020 estimated census population standing of 28,336 making it the 9th most populous county located hereabouts. Its county seat is West Union with other cities include Manchester & Seaman-West Union itself equates out to Adams’s largestcity aside from noted country seat. This area had been created out of Pike and Highland Counties back in 1797 when local citizens petitioned for new administrative boundaries - posthumously named after Bill of Rights' author John Adams controlling state preceding era Polly Madison .