Warrenton is a town in Fauquier County, Virginia, United States. The population was 6,670 at the 2000 census, and 14,634 at the 2010 estimate. It is the county seat of Fauquier County. Public schools in the town include Fauquier High School, Warrenton Middle School, Taylor Middle School and two elementary schools. There are two private schools in Warrenton: Highland School and St. John The Evangelist's Catholic School. Warrenton is at a junction of U.S. Route 15, U.S. Route 17, U.S.