Thacher Island Light

Cape Ann Light

South Tower of the Cape Ann Twin Lighthouses, ca. 1869
Cape Ann Light Show map of Massachusetts Cape Ann Light Show map of the US
Location	Cape Ann, Massachusetts
Coordinates	42°38′13″N 70°34′30″W / 42.63683°N 70.57498°W / 42.63683; -70.57498Coordinates: 42°38′13″N 70°34′30″W / 42.63683°N 70.57498°W / 42.63683; -70.57498
Year first constructed	1771
Year first lit	1861 (current structure)
Foundation	Granite (surface rock)
Construction	Cut granite
Tower shape	Conical
Markings / pattern	Natural, unpainted granite
Height	124 feet (38 m)
Focal height	166 feet (51 m)
Original lens	1st order Fresnel lens
Current lens	VRB-25
Range	17 nautical miles (31 km; 20 mi)
Characteristic	Fl R 5s
Fog signal	HORN: 2 every 60s
Admiralty number	J0276
ARLHS number	USA-105
USCG number	1-295
Twin Lights Historic District – Cape Ann Light Station
U.S. National Register of Historic Places
U.S. National Historic Landmark District
Nearest city	Rockport, Massachusetts
Area	50 acres (20 ha)
Built	1860
MPS	Lighthouses of Massachusetts TR (AD)
NRHP Reference #	71000355
Significant dates
Added to NRHP	October 07, 1971
Designated NHLD	January 3, 2001
Heritage	national historic landmark of the USA, National Register Historic District
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Thacher Island North Light

The northern lighthouse is to the right in this 2009 photo.
Location	Cape Ann, Massachusetts
Coordinates	42°38′21″N 70°34′29″W / 42.63917°N 70.57478°W / 42.63917; -70.57478
Year first constructed	1771
Year first lit	1861 (current structure)
Deactivated	1932-1988
Foundation	Granite (surface rock)
Construction	Cut granite
Tower shape	Conical
Markings / pattern	Natural, unpainted granite
Height	124 feet (38 m)
Focal height	162 feet (49 m)
Original lens	1st order Fresnel lens
Current lens	200 millimetres (7.9 in)
Characteristic	F Y
Fog signal	none
USCG number	1-305
Heritage	national historic landmark of the USA, National Register Historic District
[]

1-295

The Cape Ann Light Station on Thacher Island, off Cape Ann in Rockport, Massachusetts, is nationally significant as the last light station to be established under colonial rule and the first station in the United States to mark a navigational hazard rather than a harbor entrance. The current pair of lighthouses were built in 1861. They were both equipped with first order Fresnel lenses, which stood approximately 10 feet (3.0 m) high and weighed several tons (tonnes).

After being decommissioned in the early 1980s, the lens from the south tower was moved to the U.S. Coast Guard Museum at the United States Coast Guard Academy in New London, Connecticut. In 2013 a joint effort by the Cape Ann Museum and the Thacher Island Association brought the lens back to Cape Ann. The first order lens is now on display at the Cape Ann Museum in Gloucester, Massachusetts.

When these lights were built, there was no way to produce a flashing light and, occasionally mariners would confuse one light for another with disastrous results. The only way to create a distinction was to build more than one light. There were two lights at Plymouth and three at Nauset Beach. Gradually as it became possible to create flashes with a revolving lens system, the multiple lights were discontinued, so that while the south light is an active, Coast Guard maintained light, the north tower was discontinued in 1932. It was relighted as a Private Aid to Navigation in 1989. Both lights are now owned by the Town of Rockport and managed by the Thacher Island Association.

The station was added to the National Register of Historic Places as Twin Lights Historic District – Cape Ann Light Station on October 7, 1971, reference number 71000355. In 2001 they became the 9th light station to be recognized as a National Historic Landmark.