Alcatraz Cellhouse (Alcatraz Island federal penitentiary)

The concrete cellhouse on Alcatraz Island served as the primary cellblock during the island's period as a federal penitentiary from 1934 to 1963 and is a documented example of penal architecture adapted to a confined island site. The cellhouse and associated prison structures sit atop the island's central high ground and were repurposed from earlier U.S. Army military fortifications and detention facilities. Alcatraz is now managed as part of the Golden Gate National Recreation Area and is accessible to the public via ferry departures from Pier 33 Alcatraz Landing.