Area codes 703 and 571 are the North American Numbering Plan telephone area codes for northern Virginia, including the independent cities of Alexandria, Fairfax, Falls Church, Manassas, and Manassas Park, as well as all of Arlington and Fairfax counties and parts of Fauquier, Loudoun, Prince William, and Stafford counties. Numbering plan area 703 was created as one of the original 86 North American area codes in October 1947, and originally served the entire Commonwealth of Virginia. Area code 571 was created on March 1, 2000 as an overlay to 703.
Because of the overlay of 703 and 571, 10-digit dialing is mandatory even for local calls. Long-distance calls are dialed as eleven digits, using the prefix 1.
571 and 703 serve the following cities and towns in Virginia: Alexandria, Annandale, Ashburn, Burke, Centreville, Chantilly, Dale City, Fairfax, Falls Church, Franconia, Great Falls, Groveton, Herndon, Lake Ridge, Leesburg, Lorton, Manassas, Manassas Park, McLean, Mount Vernon, North Springfield, Oakton, Occoquan, Reston, South Riding, Springfield, Sterling, Vienna, West Springfield, and Woodbridge, plus all or part of these counties: Arlington, Fairfax, Loudoun, Prince William and Stafford.