348 Central Ave, Humarock, MA 02047, USA
Owned By: United States Air Force
Property owned and operated by the United States Air Force for its own private use. The concrete submarine watch tower still remains and serves as a landmark to those seeking entrance to the North River. The US Navy built a Radio Compass Station here after World War I. In 1942, it became an Army Coastal Artillery Gun Site. The Air Force took over the site in 1948, adding antenna towers during The Cold War, then converted it to a Family Recreation Area in 1964. No public access.
The US government began developing the northernmost land on Fourth Cliff after World War I, when it built a Navy Radio Compass Station here. These were used in sets of 3s (with Deer Island and Gloucester) to triangulate signals to help ships in and out of harbors in fog or other murky conditions. The barracks were constructed 1924.
The US Army bought all 57 acres of Fourth Cliff in 1941. In 1942, it built a Coastal Artillery Gun Site here, considered “one of the most unique and deadly coastal fortifications in New England.” It was known as battery 206 (or 208), and was part of the World War II Boston Harbor coastal defense system. There were two 6-inch Model T2 guns mounted about 60 feet above sea level, concealed with shrubbery and with a small wooden shed-like structure built over them for camouflage.
From the ocean, the area was made to look like cottages on a cliff, but it was really a military base in disguise. There was also a radar unit to guide the guns on Holly Hill, across the South River. The bunker and concrete observation tower are still there, but not open to visitors. There is some concern about erosion of the cliff, which is beginning to undercut them.
After World War II, and the advent of the jet engine, coastal defense became more of an air-based effort, not sea-based. The US Air Force, then a new branch of the military, took control of Fourth Cliff in 1948. In 1955 it was called the Fourth Cliff Research Annex. Antenna towers were added during the Cold War.
The guns platforms have now been covered up. One has a wooden picnic pavilion over it, and the other has been converted into a RV camping site. The area itself became an Air Force Family Recreation Area in 1964. The antennae were taken down, some of the buildings were restored, new cottages were built and RV pads constructed. No public access.
Habitats and Wildlife
The mouth of the North River, known as New Inlet, is the third most dangerous inlet in Massachusetts. The currents here are very dangerous and should not be navigated by paddle boats.
Historic Site: Yes
Boat Launch: No
Size: 56 acres
Hours: Not open to the public.
Parking: No public parking.
Cost: Not open to the public.
Trail Difficulty: No trails.
Facilities: No public facilities.
Boat Ramp: No
ADA Access: Yes
Scenic Views: Yes