Brewster Islands Military Reservation

The Brewster Islands Military Reservation occupies Great Brewster Island and Outer Brewster Island, featuring concrete gun emplacements, reinforced shelters, and observation posts scattered across the terrain. These installations face the Atlantic Ocean and show visible damage from decades of exposure to coastal weather.

The reservation was built in 1941 during World War II to defend Boston Harbor from attack. It served as a coastal defense system with artillery batteries and underwater mine fields controlled from the islands.

The military structures across both islands show how the United States protected its harbor during wartime. Visitors can still observe where soldiers would have stationed themselves to watch the ocean from elevated positions.

You need a boat to reach the islands, as there is no bridge or causeway from the mainland. Wear sturdy shoes and expect uneven, weathered ground when exploring the structures.

Battery Jewell on Outer Brewster Island was armed with 6-inch guns aimed at the Atlantic. Great Brewster Island housed a mine control station where operators directed underwater mines without seeing them directly.

Inception: 1941

GPS coordinates: 41.33773,-70.88774

Latest update: December 14, 2025 14:26