Fort Alcatraz

Fort Alcatraz was a United States Army coastal fortification on Alcatraz Island near the mouth of San Francisco Bay in California, part of the Third System of fixed fortifications, although very different from most other Third System works. Initially completed in 1859, it was also used for mustering and training recruits and new units for the Civil War from 1861 and began secondary use as a long-term military prison in 1868.

Major improvements, needed because of changes in artillery, began in the 1870s, but were underfunded and never fully completed, as the post came to be seen less as defense and more as a jail. The site was not used for any major works of the Endicott Board’s plan for the defense of the Bay.

A large concrete prison block was erected between 1910 and 1912. In 1933–1934, this was modernized and became the Alcatraz Federal Penitentiary.

Native Americans, known as Ohlone (A Miwok Indian word), were the earliest known inhabitants. They gathered bird eggs and other products there, but did not generally permanently live on the island.

The earliest recorded owner of Alcatraz was William Workman, of the Workman-Temple family to whom it was given by Mexican governor Pio Pico in June 1846, with the understanding that Workman would build a lighthouse on it. Workman was co-owner of Rancho La Puente and personal friend of Pio Pico. Later in 1846, acting in his capacity as Military Governor of California, John C. Fremont, champion of Manifest Destiny and leader of the Bear Flag Republic, bought the island for $5,000 in the name of the United States government from Francis Temple.

In 1850, President Millard Fillmore ordered that Alcatraz Island be set aside specifically for military purposes based upon the U.S. acquisition of California from Mexico following the Mexican–American War. Fremont had expected a large compensation for his initiative in purchasing and securing Alcatraz Island for the U.S. government, but the U.S. government later invalidated the sale and paid Fremont nothing. Fremont and his heirs sued for compensation during protracted but unsuccessful legal battles that extended into the 1890s.

Following the acquisition of California by the United States as a result of the Treaty of Guadalupe Hidalgo which ended the Mexican–American War (1848), and the onset of the California Gold Rush the following year, the U.S. Army began studying Alcatraz Island for coastal batteries to protect the entrance to San Francisco Bay. In 1853, under the direction of Zealous B. Tower, the United States Army Corps of Engineers began fortifying the island, continuing until 1859, at cost of $87,698

The start of construction was a citadel, in this case meaning a lightly fortified barracks, at the top of sandstone rock outcrops. In every other Third System works, such structures are masked from direct fire by more solid fortifications, but not here. The upper part of the island was encircled with walls built of stone and bricks abutting the rock faces, unlike most other Third System works, which laid a heavier hand on the natural landscape. Near the wharf, though, a later sallyport and a fortified barracks showed a more conventional design. A lighthouse was built and 11 cannons were fixed.