|"Castle Island" is a 22 acre (89,000 m≤) major recreation site located in South Boston on Boston Harbor, owned by the Massachusetts Department of Conservation and Recreation. First named Fort William by the British, it was renamed Fort Independence by Americans in 1779 and is one of the oldest fortified sites in British North America. Long recognized for its stategic location, the fort helped protect Boston from British attack during the War of 1812. The current "Castle" is a five sided fort built before the American Civil War, while the "Island" is now connected to the mainland by pedestrian and vehicle causeways.|
Local lore has it that an unpopular officer was walled up in the fort's dungeon following a duel in which he slayed a more popular man. Edgar Allan Poe learned of the legend while serving on Castle Island in the Army, and his short story "The Cask of Amontillado" is said to be based on it.
During the Second World War the Navy used the site for a ship degaussing station.
Today the Castle Island fort is open to tours in the summer. There is a monument to Donald McKay who built the clipper ships Flying Cloud and Sovereign of the Seas.