The Washington Metro has six lines: Red, Orange, Blue, Yellow, Green, and Silver.
The system is operated by the Washington Metropolitan Area Transit Authority, or WMATA, and serves Washington, D.C., plus parts of Maryland and Virginia. Unlike many subway systems, its lines are heavily interlined: several color-coded services share tracks through central Washington before branching toward different suburbs.
The first portion opened in 1976 on the Red Line, running between Rhode Island Avenue and Farragut North. The network expanded gradually across the metropolitan area, with the Silver Line reaching Dulles International Airport and Loudoun County in 2022. Potomac Yard, an infill station on the Yellow and Blue lines, opened in 2023.
A common mistake is counting routes by physical corridors rather than by their official color-coded services. Although multiple lines may use the same tracks and stations, WMATA officially recognizes six operating lines. The network has 98 stations and about 129 miles of route.