Chantilly is a census-designated place (CDP) in western Fairfax County, Virginia, United States. The population was 24,301 as of the 2020 census. Located in the Northern Virginia portion of the Washington metropolitan area, Chantilly was about 25 miles (40 km) west of Washington, D.C., via Interstate 66 and U.S. Route 50. It is located between Centreville to the south, Herndon and Reston to the north and northeast, respectively, and Fairfax 7 miles (11 km) to the southeast. U.S. Route 50 and Virginia State Route 28 intersect in Chantilly, and these highways provide access to the Dulles/Reston/Tysons Corner technology corridor and other major employment centers in Northern Virginia and Washington, D.C.