BEST WAY DOWNTOWN:
Ronald Reagan Washington National is located three miles (5 km) south of Washington, D.C. The airport's Web site offers some good information, including:
The District of Columbia (D.C.) taxis do not have meters and operate on a zone basis. Make sure to agree on the fare before departing the airport. Virginia and Maryland taxis have meters. If you feel you were overcharged, get a receipt, write down the taxi number, and call the DC Taxi Commission to report the incident.
Washington Flyer operates a bus service from National to the city terminal at 1517 K Street NW. From there, shuttle buses will take you to the major hotels, or you can take a taxi to your final destination. The fare is $8 one-way. The buses depart from outside the terminals about every 30 minutes for the 20-minute ride to downtown.
The Washington Metro Subway operates two lines from the airport station. If you are traveling fairly light this is a good option. The station is an easy walk from the terminals, or there is a free shuttle bus departing from in front of the terminals. The shuttle bus is a good idea in bad weather.
The Blue Line will take you to Metro Center Station at 11th and G streets NW where you can transfer to another line or take a taxi to your final destination. The Yellow line stops at L'Enfant Plaza, and Gallery Place(7th and G Streets NW). Trains leave every few minutes and take less than 20 minutes to downtown. The fare varies depending on the time but will be $1.05 to $1.25.
Various shuttle services operate at the airport. Fares vary from $8 to $35 depending on your destination. Expect it to be cheaper than a taxi but a little more expensive than the bus. Some companies require advance reservations. Visit the airport's Web site for more information.
A good idea if you are traveling to areas outside of the city like the Virginia, or Maryland suburbs. If you are only staying in the downtown area the Metro or a taxi will get you to where you want to be. All major rental car companies have desks at National.
World Airport Information
Adapted from How to Get Out of the Airport