Union Iron Works
Before San Francisco was a tech capital, it was a shipbuilding city. The Union Iron Works, established on the Potrero Point waterfront in the southeastern corner of the city, was one of the most important shipyards on the Pacific Coast from the 1880s through World War II. The yard built protected cruisers for the New Navy of the 1880s, warships that fought in the Spanish-American War, and cargo vessels that sustained the Allied effort in both world wars. The site where welders once assembled steel hulls for the U.S. Navy now hosts mixed-use development, but the history of American naval power on the Pacific begins in the mud and iron of this San Francisco shipyard.
Building the New Navy
In the 1880s, the United States Congress authorized the construction of a modern steel navy to replace the aging wooden fleet that had seen no significant investment since the Civil War. Union Iron Works won contracts to build some of the first steel warships of this New Navy, including protected cruisers and battleships. The shipyard's location on San Francisco Bay gave it access to deep water, skilled labor from the city's metalworking trades, and proximity to the Pacific, where American naval ambitions were increasingly focused. The USS Oregon, built at Union Iron Works and launched in 1893, became famous for her 14,000-mile voyage around South America to join the Battle of Santiago de Cuba in 1898.
Two World Wars
During World War I, Union Iron Works produced cargo ships and transport vessels for the war effort. The shipyard expanded dramatically during World War II, when demand for warships and merchant vessels pushed American shipyards to unprecedented production levels. Multiple slipways operated simultaneously at Potrero Point, and the workforce expanded to include women and African Americans who had previously been excluded from shipyard employment. The yard built destroyers, destroyer escorts, and cargo vessels at a pace that would have been inconceivable a decade earlier. This wartime production transformed the demographics and economics of San Francisco's industrial waterfront.
From Shipyard to Shore
After World War II, declining naval orders and competition from other shipyards led to the gradual closure of the Union Iron Works facility. The Potrero Point waterfront that once rang with riveting hammers and the screech of steel being cut has been redeveloped into a mixed-use neighborhood. The transformation mirrors a larger shift in San Francisco's economy, from manufacturing and heavy industry to technology, finance, and services. What remains of Union Iron Works is not a physical structure but a legacy: the warships that projected American power across the Pacific, the workers who built them, and the industrial culture that made San Francisco something more than a picturesque peninsula.
From the Air
The Union Iron Works site is at 37.76N, -122.38W on the Potrero Point waterfront in southeastern San Francisco, along the western shore of San Francisco Bay. The former shipyard area is now a developing mixed-use neighborhood. Nearby landmarks include Pier 70 and the Dogpatch neighborhood. Nearest airports: KSFO 7nm south, KOAK 7nm east.