Alcatraz Island

Alcatraz Island (/ˈælkəˌtræz/) is a small island about 1.25 miles offshore from San Francisco in San Francisco Bay, California, near the Golden Gate Strait. The island was developed in the mid-19th century with facilities for a lighthouse, a military fortification, and a military prison. In 1934, the island was converted into a federal prison, Alcatraz Federal Penitentiary. The strong tidal currents around the island and cold water temperatures made escape nearly impossible, giving the prison one of the most notorious reputations of its kind in American history. The prison closed on March 21, 1963, leaving the island a major tourist attraction today with nearly 1.4 million people visiting the island annually.

Alcatraz Island has the oldest operating lighthouse on the West Coast of the United States, early military fortifications, and natural features such as rock pools and a seabird colony (mostly western gulls, cormorants, and egrets). According to a 1971 documentary on the history of Alcatraz, the island measures 1,675 feet (511 m) by 590 feet (180 m) and is 135 feet (41 m) at highest point during mean tide. The total area of the island is reported to be 22 acres (8.9 ha).