Cape Ann Light Station

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.[2][3][4][5] 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).

Cape Ann Light Station

Location	Rockport, US
Coordinates	42°38′13″N 70°34′30″W
Established	1771
Cape Ann Light
South Tower of the Cape Ann Twin Lighthouses, ca. 1869
Foundation	granite (surface rock)
Construction	cut granite
Automated	1979
Height	124 feet (38 m)
Shape	conical
Markings	unpainted
Heritage	NRHP contributing property
Fog signal	HORN: 2 every 60s
First lit	1861
Focal height	166 feet (51 m)
Lens	1st order Fresnel lens (original), VRB-25 (current)
Range	17 nautical miles (31 km; 20 mi)
Characteristic	Fl R 5s
Thacher Island North Light
Coordinates	42°38′21″N 70°34′29″W
Constructed	1771
Foundation	granite (surface rock)
Construction	cut granite
Automated	1988
Height	124 feet (38 m)
Shape	conical
Markings	natural, unpainted granite
Heritage	NRHP contributing property
First lit	1861, 1989
Deactivated	1932-1988
Focal height	162 feet (49 m)
Lens	1st order Fresnel lens (original), 200 millimetres (7.9 in) (current)
Characteristic	F Y
Cape Ann Light Station (Thacher Island Twin Lights)
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 No.	71000355[1]
Significant dates
Added to NRHP	October 7, 1971
Designated NHLD	January 3, 2001

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.[5][2]