| Calf Island Military Reservation | |
| Partof: | Harbor Defenses of Boston |
| Location: | Hull, Massachusetts |
| Coordinates: | 42.3399°N -70.8962°W |
| Pushpin Map: | USA Massachusetts |
| Pushpin Map Caption: | Location in Massachusetts |
| Type: | Coastal Defense |
| Built: | 1941 |
| Builder: | United States Army |
| Used: | 1941-1946 |
| Ownership: | Massachusetts |
| Controlledby: | Boston Harbor Islands National Recreation Area |
| Battles: | World War II |
Calf Island Military Reservation was a World War II coastal defense site located on Calf Island in Hull, Massachusetts.
In 1920 there was a proposal to build a naval-type turret with two 16-inch guns on Great Brewster Island, but this was not implemented. Calf Island was also considered, but the battery was finally built (without a turret) as Fort Duvall.[1]
The Calf Island Military Reservation was built in 1941 on state land. It consisted of an early SCR-268 radar, searchlight station, and an observation post. It was returned to the state in 1946.[2]
The site today consists of the foundation of the observation tower.