A National Historic Landmark
White light flashing five times at 20 second intervals.
Also known as Cape Ann Light Station, the Twin Lights are the only surviving multiple lights on the coasts of the United States. The original 45-foot towers were constructed and lit in (1771 or 1789), making them among the oldest of America’s lighthouses. The stout 124-foot granite towers (with a focal plane of 166 feet) seen today replaced the original lights in 1861. The two towers, North and South, were constructed and placed so that when a ship puts sights on both towers, they point to true north, allowing sailors to check and adjust their compasses.
The Thacher Island Association provides a free boat service from Rockport Harbor to the island during the summer, with advance reservations. For more information visit thacherisland.org.