What Alcatraz Was Used For In The 1850s

One of the country's most notorious prisons was housed on an island in San Francisco Bay. Alcatraz prison, or "The Rock" as it came to be known, was believed to be escape-proof thanks to the surrounding shark-infested waters, which were ice-cold with strong currents. Indeed, the three men known to have escaped from the island are presumed to have drowned in the bay's waters, according to the FBI.

Though now mostly known for the prison housed on it, Alcatraz Island's location in the middle of the bay — just a stone's throw from a major American port city — made it an attractive site for other uses before it was made into a federal prison. In fact, the island was first put to use as a military installation. As one of three islands in the bay, it was in a perfect position to protect the city from potential foreign invaders. What's more, within a few years of its founding, it was already being put to use housing prisoners — almost a century before it would become the home of America's worst inmates.

Alcatraz was first a fort, then a military prison

Once gold was discovered in the area in 1849, San Francisco experienced a period of explosive growth, according to the Bureau of Prisons. In 1850, U.S. President Millard Fillmore authorized the island to be put to use as a military installation. Soon enough the island was fitted with over 100 cannons as well as housing for the soldiers charged with watching over the bay. At the time, the plan was to use the fortress to protect the city — especially its gold — from foreign invaders. A little over a decade later, concerns were raised that Confederate troops and/or sympathizers may also be interested in the city and its gold. Neither of those things ever happened, and not once were any of the island's cannons ever fired.

The island's use as a military installation wasn't limited to defensive purposes: it also got its first taste of life as a prison just a few years after it first became occupied. That's because the Army decided to house military prisoners there, and it would be a military prison for almost a century. By comparison, it was only a federal (civilian) prison for a hair under 30 years.