thumb|Donald McKay obelisk

Castle Island is a peninsula in South Boston on the shore of Boston Harbor. The landmass was an island until 1928, when it was connected to the mainland by a narrow strip of land. In 1634, Boston sought defenses farther out in the harbor, on one of the numerous islands which protected the port. In July 1634, the town decided to build a fortification on Castle Island. Deputy Governor Roger Ludlow and Captain John Mason of Dorchester supervised construction of the fort.

After the end of the King Philip's War the fortress was a site of internment of captured Native Americans who were shipped out to be sold into the Atlantic slave trade markets.

By the end of the century, the fort had been expanded to create a crossfire with the fort on Governor's Island. Lt Edward Gibbons, a first commander; and Roger Clapp, who served for several decades as an officer. Castle William was improved with brick walls and 20 cannon positions by 1705.

In 1775, Prince Hall and fourteen other men of African descent became freemasons on March 6, 1775, on the island. They were initiated in a British Army Lodge, No. 441 of the Irish Registry by J. E. Batt, Worshipful Master, on what was then still called Castle William Island. After the British Evacuation of Boston on March 17, 1776, Castle William was destroyed. After the fort was destroyed, Lieutenant Paul Revere was put in charge of rebuilding it. The rebuilt fort was named Fort Independence on December 7, 1797.

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File:1789 CastleWilliam BostonHarbor MassachusettsMagazine.jpg|Castle William, as it appeared before its destruction in 1776

File:Boston MKL Bd. 3 1890 (128589392).jpg|1890 map of Boston Harbor showing Castle Island as an island

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19th century

Beginning in 1801, a new fort on Castle Island was built by the war department. The fort helped protect Boston from British attack during the War of 1812. The island is also the site of a monument to Donald McKay, the builder of the famous clipper ships Flying Cloud and Sovereign of the Seas. The present structure, built between 1833 and 1851, is the eighth generation of forts.

Castle Island was originally some distance offshore, but land reclamation for expansion of port facilities has extended the mainland towards it, and it is now connected to the mainland by pedestrian and vehicle causeways. Today it is operated as a state park by the Massachusetts Department of Conservation and Recreation and is open to tours in the summer.

thumb|right|Castle Island during World War II

Local lore has it that an unpopular officer was walled up in the fort's dungeon following a duel in which he killed 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. In 1970, the fort was listed on the National Register of Historic Places. Tours of Fort Independence are conducted by The Castle Island Association on a seasonal schedule.

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Further reading

  • "Punishment at Hard Labor: Stephen Burroughs and the Castle Island Prison, 1785–1798." The New England Quarterly, Vol. 57, No. 2 (June 1984), pp.&nbsp;249–254.
  • Castle Island, Pleasure Bay, M Street Beach and Carson Beach Department of Conservation and Recreation
  • Castle Island Map Department of Conservation and Recreation