Alcatraz Island, sometimes informally referred to as simply Alcatraz or by its pop-culture name, The Rock, is a small island located in the middle of San Francisco Bay in California, United States. It served as a lighthouse, then a military fortification, then a military prison followed by a federal prison until 1963. It became a national recreation area in 1972 and received landmarking designations in 1976 and 1986.
Today, the island is a historic site operated by the National Park Service as part of the Golden Gate National Recreation Area and is open to tours. Visitors can reach the island by ferry ride from Pier 33, near Fisherman's Wharf in San Francisco.