Ronald Reagan Washington National Airport (IATA: DCA, ICAO: KDCA, FAA LID: DCA) is a civil airport located in Crystal City, in Arlington County, Virginia, United States, 5 miles (8.0 km) from Washington, D.C. It is the closest airport to Washington, D.C., the nation's capital, the 23rd-busiest airport in the nation, and the busiest airport in both the Washington metropolitan area and the Washington–Baltimore combined statistical area.

The airport opened in 1941 and was originally named Washington National Airport. Part of the original terminal is still in use as Terminal 1. A larger second terminal, now known as Terminal 2, opened in 1997. In 1998, Congress passed and President Bill Clinton signed a bill renaming the airport in honor of the 40th president of the United States Ronald Reagan, who was in office from 1981 to 1989.

Reagan National serves 98 nonstop destinations as of October 2023. It is a hub for American Airlines. It is an international airport, but has no immigration and customs facilities and international flights are restricted to those with U.S. Customs and Border Protection preclearance facilities, including major airports in Canada and some destinations in the Caribbean. Reagan National is also home to Coast Guard Air Station Washington.

The airport served over 25.4 million passengers in 2023, the second most of any of the three airports serving the region, and a new passenger record for the airport.