Alcatraz Island (sometimes just called Alcatraz or The Rock) is a small island in San Francisco Bay in California. It was first a lighthouse, then a military fort, then a military prison, and finally a federal prison. In 1963, it became a museum.
The name Alcatraz comes from the original Spanish name of the island, Isla de los alcatraces (Island of the pelicans). It was given that name when a Spanish explorer, Juan Manuel de Ayala, noticed the great amount of pelicans roosting on the island.
Alcatraz Island is one of many islands in the San Francisco Bay area.