Lafayette County /lɑːfeɪɛt/ is a county located in the U.S. state of Arkansas. As of the 2010 census, the population was 7,645, making it the third-least populous county in Arkansas. The county seat is Lewisville. Lafayette County was formed on October 15, 1827 and named in honor of Marquis de Lafayette, a French military hero of the American Revolutionary War. It is a dry county; therefore, the sale of alcohol is prohibited.