Mason’s Island (Algonquin: Chippachaug); an inhabited island at the mouth of the Mystic River, in Stonington, Connecticut; part of the region of Mystic, Connecticut. The island was named after Major John Mason who was granted the island in recognition of his leadership of English troops and neighboring tribal nations in the brutal defeat of the Pequod nation at Mystic. It is connected to the mainland by a causeway. Fishing is permitted from the causeway connecting Mason’s Island to Mystic. Some of the island is owned by the Mason’s Island Company and is regulated by property deeds. A quarry supplying rough granite for breakwaters (e.g. at Newport, Rhode Island) was located on the western side of the island.