Union Station is the main Railway Station in Washington. It was constructed between 1907 and 1908 as the new terminal for the Baltimore & Ohio and the Pennsylvania Railroads.

Besides serving as a train station it has become a popular place for shopping and eating with a large food court and more than 100 shops.

The train station is served by Amtrak, MARC and Virginia Railways services as well as by the Metro Trains and local buses. It opened in 1907 and at its height during WW2 some 200,000 people passed through it every day. It is also the headquarters for Amtrak.

The track area of the station is divided into upper and lower levels. On the Upper Level are tracks 7–20 which are used by MARC (weekdays) and Amtrak Acela Express, as well as a few Amtrak Regional trains. The Lower Level consists of tracks 22–29 and is used by all southbound service, including all VRE trains, as well as some northbound Amtrak services during the week. The D.C. Metrorail Red Line station is located underground at the western side of the building, and is the busiest station in the entire Metro system.