Castle Clinton National Monument is in New York City. It was originally a fort that was built to defend New York City during the War of 1812 (1812-1815). The fort served as military headquarters for the United States Army in New York during the war. In 1815, the fort was named Castle Clinton in honor of De Witt Clinton, then mayor of New York City. It was later named Castle Garden and used as an entertainment center. From 1855 until 1890, it was an immigration station, and from 1896 until 1941, it was the site of the New York Aquarium. The monument was established in 1946. For its area, see National Park System (table: National monuments) .
