Lexington County is a county located in the U.S. state of South Carolina. As of the 2020 census, the population was 293,991. Its county seat and largest community is Lexington. The county was chartered in 1785 and was named in commemoration of Lexington, Massachusetts, the site of the Battle of Lexington in the American Revolutionary War. Lexington County is the sixth-most populous county in South Carolina by population and is part of the Columbia, SC Metropolitan Statistical Area.