Washington Dulles International Airport (IATA: IAD, ICAO: KIAD, FAA LID: IAD) is an international airport in Loudoun and Fairfax counties in Virginia, United States, 26 miles (42 km) west of downtown Washington, D.C. The airport serves the Baltimore–Washington Metropolitan Area, centered on the District of Columbia. The airport is named after John Foster Dulles, the 52nd Secretary of State who served under President Dwight D. Eisenhower. The Dulles main terminal is a well-known landmark designed by Eero Saarinen. Operated by the Metropolitan Washington Airports Authority, Dulles Airport occupies 13,000 acres (52.6 km2) straddling the Loudoun-Fairfax line. Most of the airport is in the unincorporated community of Dulles, in Loudoun County, with a small portion in the unincorporated community of Chantilly in Fairfax County.
Dulles is the one of the three major airports in the larger Baltimore–Washington metropolitan area with more than 21 million passengers a year. Dulles has the most international passenger traffic of any airport in the Mid-Atlantic outside of the New York metropolitan area, including approximately 90% of the international passenger traffic in the Baltimore-Washington region. On a typical day, more than 60,000 passengers pass through Washington Dulles to and from more than 125 destinations around the world. However, Dulles Airport now ranks behind both Baltimore-Washington International Airport (BWI) and Ronald Reagan Washington National Airport (DCA) in total annual passenger boardings.