Castle Williams

Castle Williams sits on the northwest point of Governors Island, a few minutes by ferry from the southern tip of Manhattan. It is a nearly circular fort of red sandstone, about 40 feet high and 210 feet across, with walls 7 to 8 feet thick.

It was designed and built between 1807 and 1811 under Jonathan Williams, chief engineer of the Army Corps of Engineers, as one piece of the harbor defenses that also included Fort Jay on the same island and Castle Clinton at the tip of Manhattan.

The idea was to stack guns in enclosed rooms called casemates on several levels, so a small fort could put a lot of fire on the water. The design was copied along the American coast for most of the 1800s.

During the Civil War the castle housed newly recruited Union soldiers and also held Confederate enlisted men and Union deserters. By the 1880s its walls were pitted and the fort was considered obsolete as a defense.

It then settled into a second life as a military prison. It was fitted as a model prison in 1903, became part of the Army disciplinary barracks system in 1915 and 1921, and was rebuilt inside in the 1930s and 1940s with steel cells and concrete balconies in the courtyard. The Army closed it as a prison in 1965.

The Coast Guard arrived the next year and first thought of tearing it down. Instead the castle served as a community center and later as storage until the Coast Guard left the island in 1997. In 2003 Castle Williams and Fort Jay passed to the National Park Service as part of Governors Island National Monument. The building is listed on the National Register of Historic Places.