Washington Union Station is a major train station, transportation hub, and leisure destination in Washington, D.C. Opened in 1907, it is Amtrak's headquarters and the railroad's second-busiest station with annual ridership of just under 5 million and the ninth-busiest in overall passengers served in the United States. The station is the southern terminus of the Northeast Corridor, an electrified rail line extending north through major cities including Baltimore, Philadelphia, New York City, and Boston and the busiest passenger rail line in the nation.