MWRA Environmental Quality Department's Water Quality Information


The State of Boston Harbor and Massachusetts Bay
MWRA Environmental Quality Department

The Boston Harbor Islands

Aerial photograph of the Boston Harbor Islands.

A visit to the Boston Harbor Islands is a special experience. You can leave the cares of the world behind for a few hours of relaxation or adventure. Each island has its distinct topography, shoreline, history and opportunities for recreation and enjoyment. Each is small enough to explore in one day and rich enough to return to many times.


Two islands owned by MWRA are actually included in the Boston Harbor Islands National Park Area created by Congress in 1996. One is Deer Island, the location of the $3.8-billion MWRA sewage treatment plant that protects Boston Harbor and Massachusetts Bay from potential adverse impacts of greater Boston's sewer system. The other is Nut Island, for almost a hundred years the site of an MWRA treatment plant that discharged into the southern harbor.

Now, a new headworks facility is located on Nut Island, which redirects south system sewage flows through an undersea tunnel to Deer Island for treatment. Grounds and shoreline at Nut Island are now open for walking, jogging and fishing. Planning for public access has been shared with a community-based Nut Island Citizen Advisory Committee.

Grounds at Deer Island include more than 60 acres of public open space—trails and a perimeter walkway with stunning ocean views. The public is now enjoying this scenic recreation area.


Deer Island is also the site of the historic Steam Pump Station built in 1890. This National Register landmark was restored in cooperation with the Massachusetts Historical Commission and now contains exhibits and displays on the Deer Island Treatment Plant and the Boston Harbor Project. The history of Deer Island includes many interesting episodes tracing to the seventeenth century.


Organization Website Phone
Boston Harbor Islands State Park 617 727-7676
Boston Harbor Islands National Park Area 617 223-8666
Boston Online's Harbor Page — a comprehensive list of harbor-related sites