South Station, officially The Governor Michael S. Dukakis Transportation Center at South Station, is the largest railroad station and intercity bus terminal in Greater Boston and New England's second-largest transportation center after Logan International Airport. Located at the intersection of Atlantic Avenue and Summer Street in Dewey Square, Boston, Massachusetts, the historic station building was constructed in 1899 to replace the downtown terminals of several railroads. Today, it serves as a major intermodal domestic transportation hub, with service to the Greater Boston region and the Northeastern and Midwestern United States. It is used by thousands of commuter rail and intercity rail passengers daily. Connections to the rapid transit Red Line and bus rapid transit Silver Line are made through the adjacent subway station.

Intermodal passenger transport, also called mixed-mode commuting, involves using two or more modes of transportation in a journey. Mixed-mode commuting is often used to combine the strengths of various transportation options. A major goal of modern intermodal passenger transport is to reduce dependence on the automobile as the major mode of ground transportation and increase use of public transport. To assist the traveller, various intermodal journey planners such as Rome2rio and Google Transit have been devised to help travellers plan and schedule their journey.