Thacher Island is a small, uninhabited island located off the coast of Cape Ann in Massachusetts. It is known for its two historic lighthouses, which were built in the 19th century to guide ships safely through the surrounding waters. The island is part of the Thacher Island State Reservation and is accessible by boat. The island covers approximately 50 acres and features rocky shores, tidal pools, and diverse wildlife. It is a popular destination for birdwatching and offers scenic views of the Atlantic Ocean. Visitors can explore the island's trails and learn about its maritime history through interpretive signs.