Governors Island National Monument is located in Manhattan, New York City on 22 acres (89,000 m2) of Governors Island. Governors Island has played a role in the defense of New York Harbor, the city, and the nation since 1755. In October 1995 the United States Coast Guard announced it would close its largest base, at Governors Island, as a cost savings measure. On January 31, 2003, the island was conveyed to the National Trust for Historic Preservation and it was conveyed to the U.S. Department of the Interior for use as a national monument. Presidential Proclamation 7647 of February 7, 2003 formally re-affirmed the establishment of the national monument. Governors Island National Monument, open seasonally, is reached by ferry from Battery Park. Visitors can tour Fort Jay and Castle Williams, walk the Governors Island Historic District, and enjoy recreational activities, including concerts, picnics, hiking, and biking. Star-shaped Fort Jay (1806-1809) dominates the island and is one of the best preserved and largest fortifications of its type in the nation. Located inside Fort Jay’s walls are four barracks that form an interior quadrangle. Castle Williams (1807-1811) is a massive three-tier, 200-foot diameter masonry fort. Its 8-foot sandstone walls and unique casemated tiers made the Castle virtually invulnerable. Its 102 guns made the fort one of the most formidable American seacoast defenses of its era. The island affords unique and breathtaking views of New York Harbor, Manhattan, and the Statue of Liberty. Both forts are individually listed on the National Register.