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Early History of Yerba Buena Island

~5000 BC – 1932

~5000 BC

Yerba Buena Island Formed

About 200 million years ago, the land that constitutes Yerba Buena Island (YBI) and the surrounding islands in San Francisco Bay (with the exception of the man-made Treasure Island) were formed by the collision and subduction of tectonic plates.

But Yerba Buena Island only became an island around 7,000 years ago, geologists say. Earlier, at the height of the ice age, it was connected to the mainland and the other islands in San Francisco Bay. As glaciers began to melt, the sea level rose and water began to fill the Bay. (Cultural and Paleontological Resources, Treasure Island/Yerba Buena Island Redevelopment Project, 2011) 

YBI  is a natural island approximately 152 acres in size and 400 ft in height. Photograph of Bay region from space. (Satellite data from European Space Agency, 2019)

~2000 BC

Ohlone Ancestors Inhabit Yerba Buena Island and Shoals

As an institution within the San Francisco Bay Area community, the Treasure Island Museum recognizes the history of the land on which we stand, and we celebrate the Ramaytush Ohlone and the Muwekma Ohlone Tribes as flourishing members of the broader Bay Area communities today.

Stone objects, tools, bones, beads, and shell remains on Yerba Buena Island have been found dating back from 1450 BC to 1480 AD, indicating a long history of indigenous people on the island.  These objects suggest that YBI may have been used as a fishing station or permanent settlement for the Huchiun Ohlone people for many years. During this era, YBI would have provided the Ohlone with fresh water from at least one spring, as well as firewood and fishing access.

The various remains were identified during the building of the Bay Bridge in the 1930s and reexamined by archaeologists in 2002-2004 as part of the Bay Bridge East Span Project. Archaeologists believe that changes in the SF Bay shoreline caused by erosion, climate change, and sediment deposits might have buried even earlier sites of human occupation on YBI and the surrounding areas. (Cultural and Paleontological Resources, Treasure Island/Yerba Buena Island Redevelopment Project, 2011)

1822 illustration of Ohlone Native Americans paddling a tule reed boat on the San Francisco Bay by Louis Choris. (Wikimedia)


Spanish Explorers Survey the San Francisco Bay

The first European  sighting of San Francisco Bay is attributed to Don Gaspar de Portola's expedition in 1769. This site is now marked by the Ohlone-Portola Heritage Site, a National Historic Landmark, at Sweeney Ridge high above the coastal town of Pacifica.

In 1775, Juan Manuel de Ayala mapped the Bay, naming YBI Isla de las Alcatraces for the pelicans and cormorants he saw from shore. The name Isla de las Alcatraces' was mistakenly applied to the island we now know as Alcatraz by Captain Beechey in 1826. Since then, the island has also been known as Sea Bird Island, Wood Island, and Goat Island, before its name was officially changed to Yerba Buena Island in 1931.

When the Spanish arrived in the 1700s, the Ohlone lived throughout the SF Bay Area along with the Coast Miwok who lived in what is now Marin and Sonoma County. The Ohlone frequently traveled through the Bay on tule reed boats, which may have been used to access YBI. (Cultural and Paleontological Resources, Treasure Island/Yerba Buena Island Redevelopment Project, 2011)

Nautical map depicting the San Francisco Bay in 1776. (Earth Sciences & Map Library, UC Berkeley Digital Collection)



Private Ownership of Yerba Buena Island 

A series of settlers claimed and purchased YBI from the Mexican government between 1835-1867. Captain Gorham Nye received a certificate of ownership of YBI but it was primarily inhabited at that time by Nathan Spear and John Fuller, who purchased goats from Captain Nye and began grazing them on YBI. The plentiful goats on the island eventually led to a new moniker: Goat Island. (Historical Study of Yerba Buena Island, Treasure Island and their Buildings).

In 1866, after California became part of the United States, the U.S. Army confiscated the island for “military purposes” through a presidential proclamation. Over the century that followed, it remained under military control and was used for coastal defense. 

Eadweard Muybridge, a notable photographer, took many photographs of Goat Island as he began his career in San Francisco in 1867. The dramatic view from Goat Island and the natural beauty of the San Francisco Bay figured prominently in his work at that time. 

Military Post and View of the Bay on Goat Island. Photographed by Eadweard Muybridge circa 1867-1872. (The Bancroft Library, UC Berkeley)
View of the Bay on Goat Island. Photographed by Eadweard Muybridge circa 1867-1872. (The Bancroft Library, UC Berkeley)



Yerba Buena Island Lighthouse Built

The US Lighthouse Service completed construction on a 25-foot octagonal lighthouse tower on the south end of the island to help the increasing number of ships navigate the San Francisco Bay. Quarters were also built for the lighthouse keeper, who was responsible for tending to the oil-burning lamp and steam-powered fog horn. The lighthouse is still operational today, though it is not accessible to the public. The keeper’s quarters are now the home of the Coast Guard District Commander (United States Lighthouse Society).

Yerba Buena Island Lighthouse and buildings, 1933. (Historic American Buildings Survey, Library of Congress)

Postcard depicting the Yerba Buena Island lighthouse and the keeper’s quarters lighting the way for a ferry at night, c. 1915 (Herb Entwistle Postcard Collection, United States Lighthouse Society)



Establishment of Naval Training Station on YBI

The Torpedo Assembly Building was established by the US Army to store and assemble submarine mines for the defense of the Bay in 1891. Control of the island was transferred to the US Navy in 1898, following the Spanish-American War. The land was used to establish the Naval Training Station, the first naval training center on the West Coast. The station included a training and receiving ship that temporarily housed Navy recruits until they were assigned to a ship. 

The Navy began transforming the island, constructing barracks for 500 men, and a new wharf, library, schoolroom, mess hall, storehouse, and dispensary. Among the few remaining buildings from this era are the Torpedo Assembly building and the officers’ quarters on the northeastern end of the island.

The Torpedo Assembly Building was built with concrete and chiseled to look like stone masonry, and is thought to be one of the oldest reinforced concrete buildings in the US. Fleet Admiral Chester Nimitz lived in Quarters 1 from 1963-66. The commandant’s house and officers’ quarters are now referred to as the Nimitz House (or “Quarters 1”), and the Great Whites for their stately exterior. They are listed on the National Register of Historic Places and are still accessible, with permission. 

The Torpedo Assembly Building. (California Historic Military Buildings and Structures Inventory, Library of Congress)

Postcard depicting U.S. Naval Station on Yerba Buena Island, once known as Goat Island. (Courtesy of  Catherine Bauman, Treasure Island Museum Collection)



WWI and the Influenza Quarantine 

The beginning of World War I led to an influx of new residents and construction on the island. A yeoman school was constructed and recruits were housed in tent camps on the island. At one point, the small Naval Training Station on YBI housed up to 13,000 soldiers. 

However, despite its crowded conditions, YBI was a safe haven during the second wave of the Influenza pandemic (1918-1920). The Commandant quarantined 6,000 inhabitants, comprised primarily of sailors and their families, during the outbreak for 62 days, permitting no outside contact. 


In the years following WWI, the training station closed, but the Receiving Ship station remained in use until WWII. (Cultural and Paleontological Resources, Treasure Island / Yerba Buena Island Redevelopment Project, 2011)

Detention barracks mess formation at Yerba Buena Island Naval Training Station, circa 1918. (Naval History & Heritage Command)

San Francisco High School students relaxing on YBI in 1925. (Courtesy of Paul Penna)

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