Knox County, OH neighbors Licking near Mount Vernon metropolitan centre granting a 2020 estimated census population standing at 61,521 making it the 17th least populous county situated within Ohio overall. Its county seat is Mount Vernon with other towns include Gambier & Fredericktown-Mount Vernon itself corresponds out to Knox's biggesttown aside from recognized country seat. This area had been established from Fairfield and Guernsey Counties back in 1808 when local residents petitioned for new administrative boundaries - posthumously named after Revolutionary War General Henry Knox presiding region Thomas Jefferson .