Sandy Hook, low, sandy peninsula, NE N.J., projecting 5 mi (8 km) N toward New York and separating Sandy Hook Bay from the Atlantic Ocean. At the northern end is a Coast Guard station and the former Fort Hancock, which was built to protect New York harbor and was once used as a proving ground for heavy artillery. The Sandy Hook Lighthouse (85 ft/25.9 km high; built 1763) is the oldest in service in the United States. Henry Hudson's team explored this region in 1609. The British held the peninsula during the American Revolution. Sandy Hook is part of Gateway National Recreation Area.