The Port of Boston is a major seaport located in Boston Harbor and adjacent to the City of Boston. It is the largest port in Massachusetts as well as being one of the principal ports on the east coast of the United States.The Port of Boston was historically important for the growth of the City of Boston, and was originally located in what is now the downtown area of the city. Land reclamation and conversion to other uses means that downtown area no longer handles commercial traffic, although there is still considerable ferry and leisure usage of the downtown waterfront. Today the principal cargo handling facilities are located in the Boston neighborhoods of Charlestown, East Boston, and South Boston, and in the neighboring city of Everett. The Port of Boston has also been an entry point for many immigrants.

Ground transportation
The Port of Boston has access to I-90, I-93, I-95, and U.S. 1. A CSX rail yard in the Boston neighborhood of Brighton serves the port. Limited on-dock rail connections exist but are not currently used (as of 2009). There is public transit access via the MBTA Silver line SL2 route.

Massport facilities
The public facilities, operated by the Massachusetts Port Authority (Massport), are located in the neighborhoods of Charlestown, East Boston, and South Boston. Charlestown contains facilities for bulk cargo as well as for automobile shipping and processing while East Boston contains a shipyard and marina. The majority of Massport's seaport facilities are in South Boston, which contains facilities for bulk cargo, containers, seafood, and cruise ship passengers.