Alcatraz Island’s recorded history long predates the federal prison that made it famous. Ohlone peoples knew the islands and shores of San Francisco Bay before Spanish colonization. The name came from an eighteenth-century Spanish chart referring to seabirds. After the United States acquired California, President Millard Fillmore reserved Alcatraz for military purposes in 1850. Its position inside the Golden Gate made it a logical point of defense during the gold rush, when the rapidly growing port seemed vulnerable to foreign attack.

The Army installed artillery, built barracks, and completed the West Coast’s first operational lighthouse on the island. Although the fort never fired on an enemy, Alcatraz became a place of military detention during the Civil War. Its prison role expanded in later decades. The Army held deserters, insubordinate soldiers, conscientious objectors, and Native American prisoners, including Hopi men who resisted government efforts to force their children into boarding schools. A large concrete cellhouse, completed in the early twentieth century, marked the island’s transition from fortress to military prison.

The Department of Justice acquired Alcatraz in 1934 and opened a maximum-security federal penitentiary intended for prisoners considered difficult, dangerous, or escape risks. Strict routines, limited privileges, isolated cells, and the cold currents of the bay reinforced its reputation. Famous inmates included Al Capone, George Kelly, Robert Stroud, and Alvin Karpis. Several escape attempts ended in death or recapture. The 1962 disappearance of Frank Morris and brothers John and Clarence Anglin remains debated because no conclusive evidence established whether they survived the crossing.

High operating costs and deteriorating facilities led the federal government to close the penitentiary in 1963. From November 1969 to June 1971, Native activists occupied the island under the name Indians of All Tribes. They invoked treaty principles, challenged federal termination and relocation policies, and proposed a cultural and educational center. Although authorities eventually removed the remaining occupiers, the action drew international attention to Indigenous rights and influenced subsequent activism. Graffiti from the occupation survives alongside the military and prison fabric.

Alcatraz entered the Golden Gate National Recreation Area in 1972 and opened to visitors the following year. The National Park Service now preserves the cellhouse, lighthouse, fortifications, industrial buildings, gardens, nesting bird habitat, and occupation-era markings. Fire and exposure have left some structures as stabilized ruins, while salt, wind, and moisture demand constant maintenance. Ferry access controls visitation, and interpretation increasingly presents the island’s complete history rather than only its criminal legends. Alcatraz is significant as a layered federal landscape of coastal defense, incarceration, Indigenous protest, environmental recovery, and changing public memory.