Boston Harbor watershed map
The Boston Harbor Watershed, encompassing approximately 293 square miles of land area, including all or part of 45 municipalities, as well as most of downtown Boston, is located in and around historic Boston Harbor. The watershed includes the Mystic River Watershed to the north and the Neponset, Fore, Back, and Weir River Watersheds to the south.

Although the Boston Harbor Watershed is comparatively small in area, it is unique because it contains over one-sixth of the state's population, approximately 1,070,578 people (according to 1990 US Census data). This is more than any other watershed in Massachusetts. The Boston Harbor Watershed is approximately 34% urban, 27% forestland, and 3% wetland (including salt marsh habitat).

As a result of long-term community involvement, the harbor has seen dramatic improvements in water quality over the last few years. Many species that had not been seen in the harbor for years are on the rebound, including harbor porpoises, seals, river herring, and other marine species. The Boston Harbor Islands were designated as a National Recreation Area on November 12, 1996.

Watershed Priorities

  • Expand watershed association, citizen monitoring programs, and the remediation/enforcement of water quality problems
  • Continue stream flow assessment and water supply planning in the Neponset and Weir River Watersheds and work to resolve flood control issues in the Mystic River Watershed
  • Evaluate current land use and the possibility of future development within the watershed
  • Restore sensitive habitat areas by managing dams to allow for fish passage, restoring wetlands, improving the health of the harbor, and controlling invasive species of aquatic plants
  • Reduce/eliminate sewer overflows and extreme fecal coliform and nutrient levels
Boston Light

Watershed Successes

In its first year, the Corporate Wetlands Partnership received corporate donations of approximately one million dollars for wetlands restoration projects throughout Massachusetts, including sites in the Neponset Estuary, Sagamore Marsh, and the Fowl Meadow Area of Critical Environmental Concern (ACEC).

Watershed Publications

Watershed Links

Neponset River Watershed Association
Mystic River Watershed Association
Fowl Meadow and Ponkapoag Bog , (Area of Critical Environmental Concern)
Boston Harbor Islands




This information is provided by the Executive Office of Energy and Environmental Affairs, Office of Water Policy