The Massachusetts Bay Transportation Authority, often referred to as the MBTA or simply The T, is the public operator of most bus, subway, commuter rail and ferry systems in the greater Boston, Massachusetts, area. 

The MBTA is the largest transit provider in New England, and the fifth largest in the country. 

The MBTA directly operates or contracts out for service using eight different modes: heavy rail, light rail, bus rapid transit, local/express bus, trackless trolley, commuter rail, commuter boat, and paratransit. 

In Boston, 55% of all work trips and 42% of all trips into downtown are made by transit. 

The MBTA district is made up of 175 communities with a total population of 4.7 million. 

Almost three-quarters of all Massachusetts residents live within the MBTA service area.