Where was the Alcatraz Federal Penitentiary located?

The Alcatraz Federal Penitentiary or United States Penitentiary, Alcatraz Island (often referred to as Alcatraz or The Rock) was a maximum security federal prison on Alcatraz Island, 1.25 miles (2.01 km) off the coast of San Francisco, California, United States, the site of a fort since the 1850s; the main prison building was built in 1910–1912 as a United States Army military prison.

The island became adapted and used as a prison of the Federal Bureau of Prisons in August 1934 after the buildings were modernized and security increased. Given this high security and the island's location in the cold waters and strong currents of San Francisco Bay, prison operators believed Alcatraz to be escape-proof and America's strongest prison.

The prison cells typically measured 9 feet (2.7 m) by 5 feet (1.5 m) and 7 feet (2.1 m) high. The cells were primitive and lacked privacy. They were furnished with a bed, desk, washbasin, a toilet on the back wall, and few items other than a blanket.

After being closed in 1963 as a prison, today Alcatraz is operated as a public museum. It is one of San Francisco's major tourist attractions, attracting some 1.5 million visitors annually.