On a recent trip to Alcatraz with my family, we heard from the park ranger that the island used to be a military installation (before it was a federal prison). Alcatraz -as a fort – was developed in the 1850s, in the years leading up to the outbreak of the American Civil War. As our guide explained, the fort was beefed up during the hostilities in order to protect the highly valuable shipping port of San Francisco from attack by Confederate ships.
Here’s the go-to quote used on the National Park Service brochure:
I have heard foolish talk about an attempt to seize the strongholds of government under my charge. Knowing this, I have prepared for emergencies, and will defend the property of the United States with every resource at my command, and with the last drop of blood in my body. Tell that to our Southern friends! – Albert Sidney Johnston, Commander of the Department of the Pacific, U.S. Army, 1861
What capacity did the Confederate Navy have to attack? Not much. The Confederates essentially charted a couple of pirate ships to raid the Pacific coast. The CSS Alabama roamed about for a couple of weeks, with limited success. The CSS Shenandoah was more successful – meaning it raided more ships for loot. However, the CSS Shenandoah got a late start and did most of its raiding – on whaling ships mostly – after the war was over.
Was the build-up of artillery on Alcatraz a function of a general military desire to build bigger forts, which then conveniently found a rationale in the Civil War and a trumped-up, nearly fantastical threat from a non-existant Confederate Navy?
Or was there another purpose for the placement of so many cannons in the middle of San Francisco Bay?
The Union was actively working to stop secessionist movements in California, like the Los Angeles Mounted Rifles. Southern California was ultimately pacified by the presence of federal troops. And in a number of other places, San Francisco included, popular sentiment was split and contested – with many citizens favoring secession as either an independent nation or part of the Confederacy.
The cannons placed on Alcatraz in the years leading up to the Civil War, were 8-inch columbiad cannons, with an effective range over 4,000 yards. Downtown San Francisco was about 2,500 yards away. As with the Federal Hill fortifications in downtown Baltimore, might it be said that “their goal was to guarantee the allegiance of the city and the state […] to the Federal Government under threat of force?”
In 1859, when the Alcatraz fort was completed, there were 11 cannons on the island. By 1861, there were 86 cannons and 2 mortars on Alcatraz pointing north, west, and of course, south, towards San Francisco. Through the course of the war, the number of cannons grew to 111, and the size of the cannons grew as well. These cannons were never fired in anger, but there they loomed over the wall, casting a shadow over the bay.
Then the war ended and with it the secessionist threat. Spending on Alcatraz was cut dramatically, occasionally suspended entirely, and the fort dwindled in importance until the early part of the 20th Century when it was given a new purpose as a penitentiary.