Lexington County is a county located in the U.S. state of South Carolina. As of the 2010 U.S. census, 262,391 people lived there, and the 2016 U.S. census estimates, 286,186 people lived there. Its county seat and largest town is Lexington. The county was created in 1785. Its name commemorates the Battle of Lexington in the American Revolutionary War.