Potrero Point

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Potrero Point in San Francisco, California, is the location of the earliest and most important industrial facilities in the Western United States on the eastern extension of San Francisco's Potrero Hill, a natural land mass extending into San Francisco Bay south of Mission Bay. Potrero Point,[1] the point of Potrero Hill, was systematically blasted and cut, its serpentine cliffs removed. The work yielded two square miles of rock for fill and hundreds of acres of flat industrial land east of Illinois Street between 20th Street and Islais Creek.

The region has been in regular industrial use since the 1860s, first as a location of a powder magazine and small maritime industries along the steep shoreline and early industries such as Pacific Rolling Mills, and later the famous Union Iron Works plus shipyards and related production, service and shipping-related industries, coal- and gas-fired power plants and energy generating facilities that eventually became Pacific Gas and Electric (PG&E).

Centered along Twentieth Street at Illinois Street, the site contains the most extraordinary example of an historic industrial village still extant in the West. The first locomotive, typewriter, printing press, cable car equipment, the famous battleship Oregon and steel for many of San Francisco's 19th-century buildings came from the Potrero.

1918, Looking north.


Potrero Point, originally Point San Quentin, was a peninsular extension of Potrero Hill on the south east side of the city of San Francisco, marking the southern extremity of the now filled in Mission Bay in San Francisco, California.[2] By virtue of its geography, the point was a natural potrero. Potrero Point and surrounding areas have changed drastically over the past 150 years, with a small hill being all that remains.

Potrero Point drew the attention of industrialists after the California Gold Rush because it had cheap land isolated from the densely populated city center and because of its natural deep water access. Industrialists and speculators sought to exploit Potrero Point's natural advantages and to overcome the obstacle caused by the swampy Mission Bay. The natural contour of the bay shore was changed by filling, with much of the fill material was taken in the process of blasting away the serpentine hills that once rose above the point. The steep camel-back ridge extending into the bay offered deep water access connected to the Potrero Hills, the site was first cut off by the Third Street cut, and later leveled for land building.

The geography of the bay shore, with Mission Bay cutting off Potrero Point and much of the southeastern portion of the city led to the construction of Long Bridge in 1868. The bridge connected Potrero Point to the city, and extended further south to the Bayshore district. Eventually, Mission Bay was completely developed, and the shoreline south of Potrero Point was altered dramatically to suit the intense industrial construction taking place.


Early history[edit]

The Mexican landowner, Don Francisco de Haro, owned Rancho Potrero de San Francisco and ran sheep and cattle on the land for many years. After the conquest of California by the United States in the Mexican–American War, a protracted legal struggle ensued and the DeHaro family eventually lost their claim to the land.

In 1863, development along the banks of Potrero Point consisted of two powder magazines on the southern side of the steep peninsula, located so as to keep dangerous commodities away from populated areas. Heavy industry first located on the point in 1866 when six wealthy San Francisco industrialists came together to organize the Pacific Rolling Mills with the plan to roll iron from scrap, in the hope of producing homegrown iron products, including railroad iron. Access to deep water was a necessity for delivering coal from Australia to fuel the mills, firebrick and clay from Liverpool and scrap iron from around the Pacific Rim and as far away as England.

There was a lack of level ground at the site, and cutting and leveling the hill and filling in the bay became a top priority. Eventually, two square miles of Potrero Point were removed and hundreds of acres of flat industrial land was created. Within two years and after one million dollars in expenses, foundries, piers, storehouses and wharves were in place, and the first finished iron produced on the West Coast came out of the mill.

San Francisco's population growth increased along with the demand for iron products, and with the growth of railroads and street cars on the west coast, the output from PRM doubled, and doubled again. By 1873, the mill turned out rod, wire, shafts, axles, I-beams, wrought iron and hammered iron of every type needed by the growing metropolis. By the end of the 1880s the mill had five main buildings along three blocks of waterfront and employed a thousand men. Potrero Point quickly became the site for some of California's most important heavy industries, including shipbuilding and the manufacture of mining machinery, while the hill continued to be cut and the bay mudflats filled. Submarines were built nearby the Potrero Union Iron Works shipyards.

World War I[edit]

Union Iron Works output during World War I was important, and included a large number of destroyers. The Shipyards, all ships in progress and the 9,000 workers were commandeered by the United States Navy in August 1917 for the war effort, run by the Shipping Board with the happy acquiescence of Bethlehem Steel, holder of $130 million in Government contracts. From 1917 to 1924, when the government contracts were filled, the Potrero yards turned out twenty-six 1060-ton destroyers, forty 1190-ton destroyers, twelve "S" type submarines and six "R" type submarines, according to Bethlehem Steel (1949). On July 4, 1918, four destroyers were launched and four keels laid at the Union Iron Works yards, and four destroyers launched and four keels laid at the Risdon yards.

From 1914 to 1945 the northern parts of Potrero Point were the scene of major shipbuilding, repair and refitting. The Union yard was continually busy and was the principal yard in San Francisco for repairs. Between the wars, shipbuilding, and especially refitting, continued at the Potrero yards.

World War II[edit]

Before 1941, the shipyard at what is now Pier 70 produced some of its best ships. By the late 1930s, though, with war looming, Bethlehem began to modernize and upgrade the Potrero Yard. A number of new buildings were constructed, and by the time World War II began Potrero was one of the most productive shipyards in the country. During World War Two, the government once again took over the Potrero Point yards for the war effort. During the war, up to 4,000 men and women were employed, working three shifts a day. Finding skilled workers during wartime was a huge challenge, and much was done to train new workers, and to organize shipbuilding so that less skilled people could do what the highly skilled people had done before. At the height of the war effort productivity was tremendous: the destroyer escort Fieberling was built in 24 days, start to finish. Though Liberty ships and other simpler ships could be built faster, to build a modern warship in that amount of time was an incredible achievement. During the war, Bethlehem's Potrero yard produced 72 vessels (52 for combat) and repaired over 2,500 navy and commercial craft.

Bethlehem Shipyards, along with Alameda and Hunters Point, managed by Bethlehem, made the San Francisco Bay Area the most productive shipbuilding area in the U.S. during World War II.

Postwar era[edit]

After an intense period of ship repair and refitting during the war years, the Potrero point shipyards went into slow decline. From 1947 to 1953, no shipbuilding occurred and the yards became places for ship repairs, upgrades and commercial work. In the 1960s, a staging area for the Bay Area Rapid Transit underwater tube sections was established. In the 1960s, Bethlehem Steel built the largest floating drydock in the world at the Potrero site. In the 1980s, the city of San Francisco purchased the property for one dollar and the Todd Shipyard Corporation bought the plant and the equipment for $14 million and leased the site from the city. Currently, work is carried out under the name San Francisco Drydock Company.

Major businesses[edit]

Pier 70 in San Francisco is currently occupied by BAE Systems Ship Repair, which once housed the SS Oceanic, and Sims Group, a metal operator, and the Port of San Francisco currently has plans for redevelopment.

Potrero Generating Station[edit]

The Potrero Generating Station, located at the site of the first electrical power plant in California, was a 362 MW natural gas- and oil-fired power plant which supplied approximately 1/3 of the City of San Francisco's power needs. The plant was shut down in January, 2011.

Union Iron Works[edit]

The Union Iron Works, located on Potrero Point is the longest running privately owned shipyard in the country. It built the first steel hulled ship on the West coast. It also constructed several warships including USS Olympia and two Plunger-class submarines.

Manufactured gas[edit]

In 1872, Pacific Rolling Mills was joined in the Potrero by the City Gas Company, a coal gasification plant built to supply gas for lighting the city. Coal (and later fuel oil) steam generation was used to generate heat, power and electricity. The gas plant in the Potrero was for many years the largest and most important gas manufacturing plant in San Francisco. Construction began in 1870 on lots between Humboldt and Sierra streets (later renamed). Originally a coal-gas works, Springer water-gas generators were added in 1888. By 1905, PG&E had consolidated much of the power generation in the state, including the Potrero works. After the 1906 removal of the coal-gas retorts, the Potrero plant became an oil-gas facility. For fifty years the Potrero plant used gasification to drive steam turbines and power the city of San Francisco.

In 1930, transporting natural gas over long distances was employed in California, and natural gas arrived at Potrero. The Potrero gas works were put on standby status until their demolition in the 1950s.

California Sugar Refinery[edit]

Claus Spreckels, a German immigrant, began sugar production in 1867. The California Sugar Refinery outgrew its facilities at Eighth and Brannan streets and in 1881, moved to the southern part of Potrero Point where they had deep water access for the ships filled with cane from the Hawaiian island cane farms Spreckels controlled. In the 1890s, Spreckels joined with the national sugar trust. The refinery in the Potrero was renamed the Western Sugar Refinery. The huge Victorian-era brick refinery buildings were in use until demolished in 1951.

California Barrel Company[edit]

Among the variety of maritime related industries in the Potrero was a quarter mile long ropewalk and the "California Barrel Company," With five large buildings, the barrel company had three warehouses, a power generating house and the factory itself.

Other businesses[edit]

Also dating from the 1850s was the 1,000-foot-long (300 m) ropewalk of the Tubbs Cordage Company at the southern edge of Potrero Point. It was founded by two brothers in the ship chandlery business who realized the west needed rope for its growing maritime industries. They recruited a group of skilled workers from New England who formed the core of the Tubbs workforce for decades. Tubbs imported raw materials from the Philippines and became a worldwide concern. Numerous other maritime related industries had their works at Potrero.


The labor history of the shipyards at Potrero is not well documented. Bethlehem Shipbuilding, like the Union Iron Works, fought hard to keep unionization out of the shipyards. Strikes, some of them protracted, occurred periodically throughout the active shipbuilding period, including during the war years and immediately after. One important strike in the spring of 1941 halted major naval shipbuilding for a month and a half, leading to the intervention of President Roosevelt in efforts to end the strike. Members of the machinist union's local resisted the federal government and their own national leaders and persisted in the strike. They succeeded for the first time in achieving a closed shop at Bethlehem.

Historic buildings[edit]

Potrero Point is eligible for the National Register as an historic district for its contribution to three war efforts (Spanish–American War, World War I & World War II) and because of the 19th century buildings that remain. In 1994, what was then called the Landmarks Board submitted historical nominations to the Board of Supervisors for the 1917 Frederick Meyer Renaissance Revival Bethlehem Shipbuilding Corporation office building, the Charles P. Weeks designed Power House#1 built in 1912, the 1896 Union Iron Works office designed by Percy & Hamilton and the huge 1885 Machine shops. listed on the National Register of Historic Places April 17, 2014.


  • A Century of Progress 1849-1949 Bethlehem Shipbuilding Corporation
  • Port of San Francisco Waterfront Land Use Plan - City of SF Planning Dept Final EIR January 9, 1997

Landmarks Board - San Francisco Nomination Forms

  1. ^ "Potrero Point". Geographic Names Information System. United States Geological Survey. Retrieved 2009-05-04.
  2. ^ Nancy Olmsted, Mission Bay Gazeteer of Historic Places, foldout at the end of "Vanished Waters: A History of San Francisco's Mission Bay" published by the Mission Creek Conservancy, and republished by foundsf.org with their permission. From foundsf.org accessed 3/29/2015.

External links[edit]

Coordinates: 37°45′25″N 122°23′59″W / 37.75694°N 122.39972°W / 37.75694; -122.39972