Alcatraz Island decay and historic structures

Alcatraz Island contains the remains of the former U.S. Penitentiary (operated 1934–1963) whose cellhouse, workshops, and other structures show visible deterioration from marine exposure and deferred maintenance. Some buildings are stabilized for interpretation while others remain in a ruinous state, illustrating mid-20th-century federal prison architecture and coastal decay processes. The island is part of the Golden Gate National Recreation Area and is reached by ferry from Pier 33; the structures are documented and interpreted by the National Park Service.