Great Brewster Island

This largest of the Brewster islands features eroding cliffs, a salt marsh, tidal pools, and a large gull colony.

Great Brewster Island is the largest island in Boston's outer harbor at 19 acres of upland and 49 acres of intertidal area. It offers spectacular views of Boston's inner harbor, Massachusetts Bay, and Boston Lighthouse, America's oldest light station. In fact, from Great Brewster's 100 feet high bluffs, one can see four lighthouses.

While walking the island's trails, a visitor will see a salt marsh, gull breeding grounds and nurseries, the remains of a military bunker and observation post, and the stone wall foundations of summer cottages. Along the shoreline one can investigate tidal pools and, on most days, one can see lobster boats working their traps and several private boats fishing the many rock outcroppings that ring Great Brewster and the other outer islands.

There is no dock at Great Brewster Island.
Short History
Great Brewster Island was named for Elder William Brewster, the first preacher and teacher for the Plymouth Colony. Thousands of years before the English settlers named the island, Native Americans used it as a summer residence and utilized its natural resources. In more resent times the island has been home to summer cottages for local families and for U.S. soldiers who manned an observation post during WW II. The military post included 90mm rapid-fire guns, searchlight stations, and a command post that aided in controlling the harbor’s minefield.

General Information
This island of Boston Harbor Islands national park area is managed by Massachusetts Department of Conservation & Recreation (DCR).

Agency Designation: Harbor Islands Reservation
Current Use: Park purposes
Harbor Location: Outer Harbor
Acreage: 68 (upland acres: 18.61; intertidal acres: 48.95)
Highest elevation: 105 feet
Longitude: 42° 20' 25.8" North
Latitude: 70° 53' 41.0" West
Miles from Long Wharf: 8.8

Visitor Facilities & Services
9:00am - sunset
Visitor season:
Boat slips:
Visitor staff:
Guided tours:
Park boats:
Car access:
Flush toilets:
0 (capacity ea: 0)
Composting toilets:
Group campsites:
0 (capacity ea: 0)
Picnic areas:
Camping capacity:
Cooking grills:
Drinking water:
Walking trails:


On-island Circulation: The island has one path that leads to the summit of the northern bluff and several spur paths along the remains of WWII era roads and paths.


Natural History Overview
Apple trees, pear trees, sumac, beach roses, grasses, Phragmites.

Overview survey in progress.

The northern drumlin is the highest point in the outer harbor, rising to an elevation of 105 feet. Between this drumlin and the smaller drumlin to the south is a marsh area that is seasonally inundated at high tide. A sandspit, exposed at low tide, extends for nearly a mile from the southwest side of the island towards Georges Island. Mussel beds surround the island and connect Little Brewster at low tide.

Water Features
Further research required to determine whether the circa 1720s well or 1940s military water supply facilities remain.

Views and Vistas
The northern bluff offers spectacular views of the outer harbor and Boston skyline.



  • None


  • 90mm gun batteries
  • bunkers (2)

Other Structures

  • Remnants for WWII era pier and 1970s pier
  • Visitor shelter
  • Granite seawall
  • Stone wall
  • Composting toilet
Alternate Names
Island names have changed, depending on ownership and the customs of the times. What's in a Name? lists alternate names for park islands (and a few Harbor islands not within the park). Following is the known alternate name for Great Brewster Island:
  • Greater Brewster Island

Last updated: February 26, 2015

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Contact Info

Mailing Address:

15 State Street
4th Floor

Boston , MA 02109


617 223-8666

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