Deer Island Thorofare Light

Deer Island Thorofare Light stands on a small island at the west end of the Deer Island Thorofare and Merchant Row, two east‑west passages that separate Deer Isle from Isle au Haut in Penobscot Bay, Maine. The lantern marks the channel about 1.8 nmi west‑southwest of the town of Stonington.

The tower is a square brick structure on a masonry foundation, painted white with a black lantern and trim. Its focal plane is 52 ft above sea level. Originally equipped with a fourth‑order Fresnel lens, the present optic is a 250 mm lens that produces a flashing white characteristic every six seconds (Fl W 6s). The beam reaches eight nautical miles. A foghorn sounds one blast every fifteen seconds on a continuous basis.

The station was established and first lit in 1857, using the small square brick tower that still stands. In 1958 the light was automated, ending the need for a full‑time keeper. The keeper’s house burned the following year, and the remaining outbuildings were removed shortly thereafter.

The light remains active. Stewardship of the island passed in 1998 to the Island Heritage Trust, which preserves the site as a bird sanctuary.

Light and tower

It was first lit in 1857. It was automated in 1958.