Alcatraz Island size comparison
0.09 km2 / 0.03 mile2
Alcatraz Island is located in San Francisco Bay, 1.25 miles (2.01 km) offshore from San Francisco, California. The small island was developed with facilities for a lighthouse, a military fortification, a military prison, and a federal prison from 1934 until 21 March 1963. The water currents around the island were high at all times, which presumably decreased the chance of an inmate escaping. In 1972, Alcatraz became part of Golden Gate National Recreation Area and received designation as a National Historic Landmark in 1986.