Plymouth Light, also known as Gurnet Light, is an historic lighthouse

Lighthouse

A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses or, in older times, from a fire, and used as an aid to navigation for maritime pilots at sea or on inland waterways....

 located on Gurnet Point

Gurnet Point, Massachusetts

Gurnet Point, also known as The Gurnet, is located at the end of the peninsula at the entrance to Plymouth Bay in Plymouth, Massachusetts, and is a headland and the small private settlement located on it. The Pilgrims who settled Plymouth in 1620 named it Gurnett’s Nose for its resemblance to...

 at the entrance to Plymouth Bay

Plymouth Bay

Plymouth Bay is the name of a small, well-protected bay of the Atlantic Ocean on the western shore of larger Cape Cod Bay along the coastline of the Commonwealth of Massachusetts...

 in the town of Plymouth, Massachusetts. The light is accessible only by passing through the town of Duxbury, which lies to the north.

The original lighthouse was built in 1768, burned down and rebuilt in 1801, when the single light became a pair, and rebuilt again in 1842, again as a pair. The light gradually lost importance as Plymouth Harbor silted up and lost most of its traffic. Then, when the Cape Cod Canal

Cape Cod Canal

The Cape Cod Canal is an artificial waterway traversing the narrow neck of land that joins Cape Cod to mainland Massachusetts.Part of the Atlantic Intracoastal Waterway, the canal is roughly 17.4 miles long and connects Cape Cod Bay in the north to Buzzards Bay in the south...

 opened in 1914, there was a significant increase in vessel traffic past the light. The northeast tower was torn down and the remaining tower upgraded from a sixth order Fresnel lens

Fresnel lens

A Fresnel lens is a type of lens originally developed by French physicist Augustin-Jean Fresnel for lighthouses.The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design...

 to one of the fourth order. The fourth order lens is now on display at the Lifesaving Museum in Hull, Massachusetts

Hull, Massachusetts

Hull is a peninsula town in Plymouth County, Massachusetts, United States. The population was 10,293 at the 2010 census. Hull is the smallest town by land area in Plymouth County and the fourth smallest in the state...

. The light is the oldest wooden lighthouse in the United States. The light was relocated approximately 140 ft (40m) to the north in December 1998 because of beach erosion. The property and the Duxbury Pier Light

Duxbury Pier Light

Duxbury Pier lighthouse also called Duxbury Light is a lighthouse located in Plymouth Harbor, Massachusetts. Duxbury Pier Light was built in 1871 on the north side of the main channel in Plymouth Harbor to mark the dangerous shoal off Saquish Head...

, in open water 2.3 nmi (4.3 km) to the SW are both mananged by Project Gurnet and Bug Lights, Inc.

The actual light is 102 feet (31 m) above Mean High Water

Tide

Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....

. Its white light is visible for 17 nautical miles (31.5 km); its red sector, which covers Mary Ann Rocks, is visible 15 miles (24.1 km).

Plymouth Light was listed on the National Register of Historic Places as Plymouth Light Station on March 8, 1977, reference number 77000655.