Cape Ann Light Station

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
Coordinates	42°38′12.444″N 70°34′29.752″W
Area	50 acres (20 ha)
Built	1860
MPS	Lighthouses of Massachusetts TR (AD)
NRHP reference No.	71000355
Significant dates
Added to NRHP	October 07, 1971
Designated NHLD	January 3, 2001

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.

Cape Ann Light

Cape Ann Light

South Tower of the Cape Ann Twin Lighthouses, ca. 1869
Location	Cape Ann, Massachusetts
Coordinates	42°38′13″N 70°34′30″W
Constructed	1771
Foundation	Granite (surface rock)
Construction	Cut granite
Automated	1979
Height	124 feet (38 m)
Shape	Conical
Markings	Natural, unpainted granite
Heritage	National Historic Landmark, National Register of Historic Places listed place
Fog signal	HORN: 2 every 60s
Light
First lit	1861 (current structure)
Focal height	166 feet (51 m)
Lens	1st order Fresnel lens
Range	17 nautical miles (31 km; 20 mi)
Characteristic	Fl R 5s

Cape Ann Light is the southern lighthouse that comprise the station.

Thacher Island North Light

Thacher Island North Light

The northern lighthouse is to the right in this 2009 photo.
Location	Cape Ann, Massachusetts
Coordinates	42°38′13″N 70°34′30″W
Constructed	1771
Foundation	Granite (surface rock)
Construction	Cut granite
Automated	1988
Height	124 feet (38 m)
Shape	Conical
Markings	Natural, unpainted granite
Heritage	National Historic Landmark, National Register of Historic Places listed place
Fog signal	none
Light
First lit	1861 (current structure)
Deactivated	1932-1988
Focal height	162 feet (49 m)
Lens	1st order Fresnel lens
Characteristic	F Y

Thacher Island Lighthouses in 2009

Thacher Island North Light is the northern most lighthouse that comprise the station.

Nomenclature

• The south light's official name in the US Coast Guard Light List is Cape Ann Light, number 1-295.
• The north light's official name is Thacher Island North Light, number 1-305.
• The National Historic Landmark listing name is Twin Lights Historic District—Cape Ann Light Station.
• The lights are known locally as the Twin Lights or Thacher Island Lights.

See also

• National Register of Historic Places listings in Essex County, Massachusetts