Interstate 66 wanders out of northwest Washington, DC, into Arlington, Virginia, and through some of Washington's western suburbs, then heads through more mountainous territory before emptying onto Interstate 81 south of Winchester, for a total length of about 75 miles. I-66 has a busy interchange with the Capital Beltway (Interstate 495) in Fairfax County and access to the Dulles Airport from Centreville via Virginia Route 28; part of the Washington Metro's Orange Line also runs along its median, including the Vienna station.