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.