Sullivan Square is an MBTA subway station serving the Orange Line, located just west of the Sullivan Square traffic circle in the Charlestown neighborhood of Boston. Located adjacent to the East Somerville area of Somerville, it is also a major bus transfer point. It is named after nearby Sullivan Square, itself named for James Sullivan, an early 19th-century Governor of Massachusetts and first president of the Middlesex Canal Co. A plaque commemorating the canal is on the column right of the entrance to the station.Opened April 7, 1975 as part of the Haymarket North Extension, the station has three tracks and two platforms, and is located under a double-decked elevated section of Interstate 93. The current station replaced an older structure built in 1901, which had been a major transfer point on the Charlestown Elevated, a predecessor of the Orange Line.Like all Orange Line stations, both the subway platforms and all bus connections are fully wheelchair accessible.HistorySullivan Square stands on what was once a narrow neck of land referred to as the Charlestown Neck, an area that was originally a thin strip of land connecting the Charlestown Peninsula with present-day East Somerville. Being in a narrow place between larger land masses made Sullivan Square a place where transportation routes naturally converged, and various transportation facilities developed here over the years.