San Francisco Bay

San Francisco Bay is a shallow estuary in the US state of California. It is surrounded by a contiguous region known as the San Francisco Bay Area (often simply "the Bay Area"), and is dominated by the large cities of San Jose, San Francisco and Oakland.

San Francisco Bay drains water from approximately 40 percent of California. Water from the Sacramento and San Joaquin rivers, and from the Sierra Nevada mountains, flow into Suisun Bay, which then travels through the Carquinez Strait to meet with the Napa River at the entrance to San Pablo Bay, which connects at its south end to San Francisco Bay. The Guadalupe River enters the bay at its southernmost point in San Jose. The Guadalupe drains water from the Santa Cruz mountains and Hamilton Mountain ranges in southernmost San Jose. It enters the bay at the town of Alviso. It then connects to the Pacific Ocean via the Golden Gate strait. However, this entire group of interconnected bays is often called the San Francisco Bay. The bay was designated a Ramsar Wetland of International Importance on February 2, 2012.

San Francisco Bay
Coordinates37°39′17″N 122°14′15″W / 37.6546543°N 122.2374676°W[1]Coordinates: 37°39′17″N 122°14′15″W / 37.6546543°N 122.2374676°W[1]
River sourcesSacramento River
San Joaquin River
Petaluma River
Napa River
Guadalupe River
Ocean/sea sourcesPacific Ocean
Basin countriesUnited States
Max. length97 km (60 mi)
Max. width19 km (12 mi)
Surface area400–1,600 sq mi (1,000–4,100 km2)
SettlementsSan Jose
San Francisco
Official nameSan Francisco Bay/Estuary (SFBE)
DesignatedFebruary 2, 2013
Reference no.2097[2]
SF-Marin-Pt Reyes aerial panorama
Aerial panorama of the northern Bay, the Bay Bridge, Golden Gate, and Marin Headlands on a clear morning. November 2014 photo by Doc Searls.


The bay covers somewhere between 400 and 1,600 square miles (1,000–4,000 km2), depending on which sub-bays (such as San Pablo Bay), estuaries, wetlands, and so on are included in the measurement.[3][4] The main part of the bay measures three to twelve miles (5–19 km) wide east-to-west and somewhere between 48 miles (77 km)1 and 60 miles (97 km)2 north-to-south. It is the largest Pacific estuary in the Americas.

The bay was navigable as far south as San Jose until the 1850s, when hydraulic mining released massive amounts of sediment from the rivers that settled in those parts of the bay that had little or no current. Later, wetlands and inlets were deliberately filled in, reducing the Bay's size since the mid-19th century by as much as one third. Recently, large areas of wetlands have been restored, further confusing the issue of the Bay's size. Despite its value as a waterway and harbor, many thousands of acres of marshy wetlands at the edges of the bay were, for many years, considered wasted space. As a result, soil excavated for building projects or dredged from channels was often dumped onto the wetlands and other parts of the bay as landfill.

From the mid-19th century through the late 20th century, more than a third of the original bay was filled and often built on. The deep, damp soil in these areas is subject to soil liquefaction during earthquakes, and most of the major damage close to the Bay in the Loma Prieta earthquake of 1989 occurred to structures on these areas.

The Marina District of San Francisco, hard hit by the 1989 earthquake, was built on fill that had been placed there for the Panama-Pacific International Exposition, although liquefaction did not occur on a large scale. In the 1990s, San Francisco International Airport proposed filling in hundreds more acres to extend its overcrowded international runways in exchange for purchasing other parts of the bay and converting them back to wetlands. The idea was, and remains, controversial. (For further details, see the "Bay Fill and Depth Profile" section.)

SF, Bay Bridge and Oakland 2014
San Francisco, Oakland, and the Bay Bridge, 2014

There are five large islands in San Francisco Bay. Alameda, the largest island, was created when a shipping lane was cut to form the Port of Oakland in 1901. It is now a suburban community. Angel Island was known as "Ellis Island West" because it served as the entry point for immigrants from East Asia. It is now a state park accessible by ferry. Mountainous Yerba Buena Island is pierced by a tunnel linking the east and west spans of the San Francisco–Oakland Bay Bridge. Attached to the north is the artificial and flat Treasure Island, site of the 1939 Golden Gate International Exposition. From the Second World War until the 1990s, both islands served as military bases and are now being redeveloped. Isolated in the center of the Bay is Alcatraz, the site of the famous federal penitentiary. The federal prison on Alcatraz Island no longer functions, but the complex is a popular tourist site. Despite its name, Mare Island in the northern part of the bay is a peninsula rather than an island.

Panorama of San Francisco Bay, and the city skyline seen from Marin County in the Golden Gate National Recreation Area.
Panorama of San Francisco Bay, and the city skyline seen from Marin County in the Golden Gate National Recreation Area.


San Francisco Bay is thought to represent a down-warping of the Earth's crust between the San Andreas Fault to the west and the Hayward Fault to the east, though the precise nature of this remains under study. About 560,000 years ago, a tectonic shift caused the large inland Lake Corcoran to spill out the central valley and through the Carquinez Strait, carving out sediment and forming canyons in what is now the northern part of the San Francisco Bay and Golden Gate strait.[5]

Until the last ice age, the basin which is now filled by the San Francisco Bay was a large linear valley with small hills, similar to most of the valleys of the Coast Ranges. As the great ice sheets began to melt, around 11,000 years ago, the sea level started to rise. By 5000 BC the sea level rose 300 feet (90 m), filling the valley with water from the Pacific.[6] The valley become a bay, and the small hills became islands.


1781 Cañizares Map of San Francisco Bay.pdf
Cañizares Map of San Francisco Bay

From 15,000 – 10,000 years ago, the Ohlone tribe inhabited the area that is now the San Francisco Bay. The natives were displaced 5,000 years ago as the bay filled with water due to the rising sea level at the end of the ice age.[7]

The first European to see San Francisco Bay is likely N. de Morena who was left at New Albion at Drakes Bay in Marin County, California by Sir Francis Drake in 1579 and then walked to Mexico.[8][9]

The first recorded European discovery of San Francisco Bay was on November 4, 1769 when Spanish explorer Gaspar de Portolà, unable to find the port of Monterey, California, continued north close to what is now Pacifica and reached the summit of the 1,200-foot-high (370 m) Sweeney Ridge, now marked as the place where he first sighted San Francisco Bay. Portolá and his party did not realize what they had discovered, thinking they had arrived at a large arm of what is now called Drakes Bay.[10] At the time, Drakes Bay went by the name Bahia de San Francisco and thus both bodies of water became associated with the name. Eventually, the larger, more important body of water fully appropriated the name San Francisco Bay.

The first European to enter the bay is believed to have been the Spanish explorer Juan de Ayala, who passed through the Golden Gate on August 5, 1775 in his ship the San Carlos, and moored in a bay of Angel Island now known as Ayala Cove. Ayala continued to explore the Bay area and the expedition's cartographer, José de Cañizares, gathered the information necessary to produce the first map of the San Francisco Bay area. A number of place names survive (anglicized) from that first map, including Point Reyes, Angel Island, Farallon Islands and Alcatraz Island.

The United States seized the region from Mexico during the Mexican–American War (1846–1848). On February 2, 1848, the Mexican province of Alta California was annexed to the U.S. with the signing of the Treaty of Guadalupe Hidalgo. A year and a half later, California requested to join the United States on December 3, 1849 and was accepted as the 31st State of the Union on September 9, 1850.

The bay became the center of American settlement and commerce in the Far West through most of the remainder of the 19th century. During the California Gold Rush (1848–1855), San Francisco Bay suddenly became one of the world's great seaports, dominating shipping in the American West until the last years of the 19th century. The bay's regional importance increased further when the First Transcontinental Railroad was connected to its western terminus at Alameda on September 6, 1869.[11] The terminus was switched to the Oakland Long Wharf two months later on November 8, 1869.[12]

Duck Hunt Marshy Shoreline San Francisco Bay Alameda County california
Duck hunting on the Bay, 1915

During the 20th century, the bay was subject to the Reber Plan, which would have filled in parts of the bay in order to increase industrial activity along the waterfront. In 1959, the United States Army Corps of Engineers released a report stating that if current infill trends continued, the bay would be as big as a shipping channel by 2020. This news created the Save the Bay movement in 1960, which mobilized to stop the infill of wetlands and the bay in general, which had shrunk to two-thirds of its size in the century before 1961.[13]

San Francisco Bay continues to support some of the densest industrial production and urban settlement in the United States. The San Francisco Bay Area is the American West's second-largest urban area with approximately seven million residents.[14]


Despite its urban and industrial character, San Francisco Bay and the Sacramento-San Joaquin Delta remain perhaps California's most important ecological habitats. California's Dungeness crab, California halibut, and Pacific salmon fisheries rely on the bay as a nursery. The few remaining salt marshes now represent most of California's remaining salt marsh, supporting a number of endangered species and providing key ecosystem services such as filtering pollutants and sediments from the rivers. San Francisco Bay is recognized for protection by the California Bays and Estuaries Policy, with oversight provided by the San Francisco Estuary Partnership.[15]

San Francisco Bay c. 1770–1820

Most famously, the bay is a key link in the Pacific Flyway. Millions of waterfowl annually use the bay shallows as a refuge. Two endangered species of birds are found here: the California least tern and the Ridgway's Rail. Exposed bay muds provide important feeding areas for shorebirds, but underlying layers of bay mud pose geological hazards for structures near many parts of the bay perimeter. San Francisco Bay provided the nation's first wildlife refuge, Oakland's artificial Lake Merritt, constructed in the 1860s, and America's first urban National Wildlife Refuge, the Don Edwards San Francisco Bay National Wildlife Refuge (SFBNWR) in 1972. The Bay is also plagued by non-native species.

Salt produced from San Francisco Bay is produced in salt evaporation ponds and is shipped throughout the Western United States to bakeries, canneries, fisheries, cheese makers and other food industries and used to de-ice winter highways, clean kidney dialysis machines, for animal nutrition, and in many industries. Many companies have produced salt in the Bay, with the Leslie Salt Company the largest private land owner in the Bay Area in the 1940s.[16][17]

Low-salinity salt ponds mirror the ecosystem of the bay, with fish and fish-eating birds in abundance. Mid-salinity ponds support dense populations of brine shrimp, which provide a rich food source for millions of shorebirds. Only salt-tolerant micro-algae survive in the high salinity ponds, and impart a deep red color to these ponds from the pigment within the algae protoplasm.

The seasonal range of water temperature in the Bay is from January's 53 °F (12 °C) to September's 60 °F (16 °C) when measured at Fort Point, which is near the southern end of the Golden Gate Bridge and at the entrance to San Francisco Bay.[18]

For the first time in 65 years, Pacific Harbor Porpoise (Phocoena phocoena) returned to the Bay in 2009.[19] Golden Gate Cetacean Research, a non-profit organization focused on research on cetaceans, has developed a photo-identification database enabling the scientists to identify specific porpoise individuals and is trying to ascertain whether a healthier bay has brought their return.[20] Pacific harbor porpoise range from Point Conception, California to Alaska and across to the Kamchatka Peninsula and Japan. Recent genetic studies show that there is a local stock from San Francisco to the Russian River and that eastern Pacific coastal populations rarely migrate far, unlike western Atlantic Harbor porpoise.[21]


Industrial, mining, and other uses of mercury have resulted in a widespread distribution in the bay, with uptake in the bay's phytoplankton and contamination of its sportfish.[22] In January 1971, two Standard Oil tankers collided in the bay, creating an 800,000-U.S.-gallon (3,000,000-liter) oil spill disaster, which spurred environmental protection of the bay. In November 2007, a ship named COSCO Busan collided with the San Francisco–Oakland Bay Bridge and spilled over 58,000 U.S. gallons (220,000 liters) of bunker fuel, creating the largest oil spill in the region since 1996.[23]

The Bay was once considered a hotspot for polybrominated diphenyl ether (PBDE) flame retardants used to make upholstered furniture and infant care items less flammable. PBDEs have been largely phased out and replaced with alternative phosphate flame retardants. A 2019 San Francisco Estuary Institute (SFEI) study assayed a wide range of these newer flame retardant chemicals in Bay waters, bivalve California mussels (Mytilus californianus), and harbor seals (Phoca vitulina) which haul out in Corkscrew Slough[24] on Bair Island in San Mateo County, with phosphate flame retardant contaminants such as tris(1,3-dichloro-2-propyl)phosphate (TDCPP) and triphenyl phosphate (TPhP) found at levels comparable to thresholds for aquatic toxicity.[25]

City skyline through the fog, from the Golden Gate National Recreation Area.
City skyline through the fog, from the Golden Gate National Recreation Area.

Bay fill and depth profile

Boats in San Francisco bay
Cargo ships in San Francisco bay in 2012

San Francisco Bay's profile changed dramatically in the late 19th century and again with the initiation of dredging by the US Army Corps of Engineers in the 20th century. Before about 1860, most bay shores (with the exception of rocky shores, such as those in Carquinez Strait; along Marin shoreline; Point Richmond; Golden Gate area) contained extensive wetlands that graded nearly invisibly from freshwater wetlands to salt marsh and then tidal mudflat. A deep channel ran through the center of the bay, following the ancient drowned river valley.

In the 1860s and continuing into the early 20th century, miners dumped staggering quantities of mud and gravel from hydraulic mining operations into the upper Sacramento and San Joaquin Rivers. GK Gilbert's estimates of debris total more than eight times the amount of rock and dirt moved during construction of the Panama Canal. This material flowed down the rivers, progressively eroding into finer and finer sediment, until it reached the bay system. Here some of it settled, eventually filling in Suisun Bay, San Pablo Bay, and San Francisco Bay, in decreasing order of severity.

By the end of the 19th century, these "slickens" had filled in much of the shallow bay flats, raising the entire bay profile. New marshes were created in some areas.

In the decades surrounding 1900, at the behest of local political officials and following Congressional orders, the US Army Corps began dredging the Sacramento and San Joaquin Rivers and the deep channels of San Francisco Bay. This work has continued without interruption ever since an enormous federal subsidy to San Francisco Bay shipping. Some of the dredge spoils were initially dumped in the bay shallows (including helping to create Treasure Island on the former shoals to the north of Yerba Buena Island) and used to raise an island in the Sacramento-San Joaquin Delta. The net effect of dredging has been to maintain a narrow deep channel—deeper perhaps than the original bay channel—through a much shallower bay. At the same time, most of the marsh areas have been filled or blocked off from the bay by dikes.

Large ships transiting the bay must follow deep underwater channels that are maintained by frequent dredging as the average depth of the bay is only as deep as a swimming pool—approximately 12 to 15 ft (4–5 m). Between Hayward and San Mateo to San Jose it is 12 to 36 in (30–90 cm). The deepest part of the bay is under and out of the Golden Gate Bridge, at 372 ft (113 m).[26]

In the late 1990s, a 12-year harbor-deepening project for the Port of Oakland began; it was largely completed by September 2009. Previously, the bay waters and harbor facilities only allowed for ships with a draft of 46 ft (14 m), but dredging activities undertaken by the United States Army Corps of Engineers in partnership with the Port of Oakland succeeded in providing access for vessels with a 50-foot (15 m) draft. Four dredging companies were employed in the US$432 million project, with $244 million paid for with federal funds and $188 million supplied by the Port of Oakland. Some six million cubic yards (160 million cubic feet; 4.6 million cubic metres) of mud from the dredging was deposited at the western edge of Middle Harbor Shoreline Park to become a 188-acre (0.294 sq mi; 0.76 km2) shallow-water wetlands habitat for marine and shore life.[27][28] Further dredging followed in 2011, to maintain the navigation channel.[29][30] This dredging enabled the arrival of the largest container ship ever to enter the San Francisco Bay, the MSC Fabiola. Bay pilots trained for the visit on a simulator at the California Maritime Academy for over a year. The ship arrived drawing less than its full draft of 50 feet 10 inches (15.5 m) because it held only three-quarters of a load after its stop in Long Beach.[31]


San Francisco Bay aerial view
San Francisco Bay and the Golden Gate Bridge, looking southeast towards the City and East Bay

San Francisco Bay was traversed by watercraft since long before the coming of Europeans. Indigenous peoples used canoes to fish and clam along the shoreline. The era of sail brought ships that connected the area to the rest of the world—and served as early ferries and freighters within the Bay and between the Bay and inland ports, such as Sacramento and Stockton. These were gradually replaced by steam-powered vessels starting in the late 19th century. Several shipyards were early established around the Bay, augmented during wartime. (e.g., the Kaiser Shipyards (Richmond Shipyards) near Richmond in 1940 for World War II for construction of revolutionary mass-produced, assembly line Liberty and Victory cargo ships)

San Francisco Bay is spanned by nine bridges, eight of which carry cars.

The Transbay Tube, an underwater rail tunnel, carries BART services between Oakland and San Francisco.

Prior to the bridges and, later, the Transbay Tube, transbay transportation was dominated by fleets of ferryboats operated by the Southern Pacific Railroad and the Key System transit company. However, in recent decades, ferries have returned, primarily serving commuters from Marin County, relieving the traffic bottleneck of the Golden Gate Bridge. (See article Ferries of San Francisco Bay).

Port Of Oakland California
Port of Oakland California

The bay also continues to serve as a major seaport. The Port of Oakland is one of the largest cargo ports in the United States, while the Port of Richmond and the Port of San Francisco provide smaller services.


San Francisco Bay is a mecca for sailors (boats, as well as windsurfing and kitesurfing), due to consistent strong westerly/northwesterly thermally-generated winds – Beaufort force 6 (15–25 knots, 17–29 mph, 8–13 m/s) is common on summer afternoons – and protection from large open ocean swells. Yachting and yacht racing are popular pastimes and the San Francisco Bay Area is home to many of the world's top sailors. A shoreline bicycle and pedestrian trail known as the San Francisco Bay Trail encircles the edge of the bay. The San Francisco Bay Area Water Trail, a growing network of launching and landing sites around the Bay for non-motorized small boat users (such as kayakers) is being developed. Parks and protected areas around the bay include Eden Landing Ecological Reserve, Hayward Regional Shoreline, Don Edwards San Francisco Bay National Wildlife Refuge, Hayward Shoreline Interpretive Center, Crown Memorial State Beach, Eastshore State Park, Point Isabel Regional Shoreline, Brooks Island Regional Shoreline, and César Chávez Park.

The California Office of Environmental Health Hazard Assessment (OEHHA) has developed a safe eating advisory for fish caught in the San Francisco Bay based on levels of mercury or PCBs found in local species.[32]

The San Francisco Bay Area Water Trail is a planned system of designated trailheads designed to improve non-motorized small boat access to the bay. The California Coastal Conservancy approved funding in March 2011 to begin implementation of the water trail.

San Francisco Bay panorama with a view of sailboats, kite boarders, and the Crissy Field Beach.
San Francisco Bay panorama with a view of sailboats, kite boarders, and the Crissy Field Beach.


San Francisco from Forbes Island pier 39, 544

San Francisco from Forbes Island, pier 39

AlbertBierstadt-San Francisco Bay

"San Francisco Bay", painting by Albert Bierstadt, 1871–73


The City of Berkeley, the Bay and Marin County in the background as seen from the Claremont Canyon reserve


Mount Tamalpais view across San Pablo Bay at Point Pinole Regional Shoreline in Richmond

San Francisco Bay from the air in May 2010 01

Looking north into San Pablo Bay at the Richmond-San Rafael Bridge, 2010

Alcatraz dawn 2005-01-07

Alcatraz at dawn on San Francisco Bay


Aerial view of Golden Gate and the northern Bay, looking east from the Pacific


People also swim recreationally, at Kellar Beach in Richmond's Miller/Knox Regional Shoreline.

Oil spill in san francisc bay 1

Oil Spill in the Bay

RMS Queen Mary 2 in san francisco bay

RMS Queen Mary 2 in San Francisco Bay

Fort Baker on San Francisco Bay

Fort Baker on San Francisco Bay, just east of the Golden Gate

San Francisco Bay NASA World Wind Globe

NASA satellite image, showing water flow

View from Mission Peak 2

Salt ponds at the southern tip of the bay

Golden Gate Bridge and San Francisco Bay

The bay seen in July 2010

Ships in San Francisco Bay aerial

Ships at anchor in the bay

See also


  1. ^ "San Francisco Bay". Geographic Names Information System. United States Geological Survey. January 19, 1981. Retrieved January 2, 2017.
  2. ^ "San Francisco Bay/Estuary (SFBE)". Ramsar Sites Information Service. Retrieved April 25, 2018.
  3. ^ Symphonies in Steel: San Francisco – Oakland Bay Bridge and the Golden Gate
  4. ^ San Francisco Bay Watershed Database and Mapping Project Archived October 30, 2004, at the Wayback Machine
  5. ^ "The Formation of San Francisco Bay" (PDF). KQED education. Retrieved June 4, 2018.
  6. ^ Yabrove, Daniel (December 9, 2013). "How the Bay was Born". Save The Bay Blog. Save The Bay. Retrieved June 4, 2018.
  7. ^ Olmsted, Nancy J. "Water on the Land—The Coast People". FoundSF. Retrieved June 4, 2018.
  9. ^ Charles F. Lumis, ed. (1900). "Narrative of the Pilot Morera, who passed through the North Sea to the South Sea through the Strait". The Land of Sunshine, The Magazine of California and the West (February). pp. 184–186.
  10. ^ The representations of San Francisco (California): a portable harbor in the fragile geography of the North Pacific.
  11. ^ Alta California, September 7, 1869
  12. ^
  13. ^ "History". Save the Bay. Retrieved July 14, 2015.
  14. ^ "Bay Area Census". Retrieved 2018-10-31.
  15. ^ State Water Resources Control Board Water Quality Control Policy for the Enclosed Bays and Estuaries of California (1974) State of California
  16. ^ Spatial History Project
  17. ^ Hidden Ecologies » Blog Archive » Arden Salt Works
  18. ^ Osborn, Liz. "Average Ocean Water Temperatures at San Francisco". Current Results Nexus. Retrieved October 19, 2013.
  19. ^ David Perlman (November 8, 2010). "Porpoises return to SF Bay – scientists study why". San Francisco Chronicle. Retrieved July 25, 2011.
  20. ^ "Harbor Porpoise Project". Golden Gate Cetacean Research. Retrieved July 25, 2011.
  21. ^ Harbor Porpoise (Phocoena phocoena): San Francisco-Russian River Stock (PDF) (Report). National Marine Fisheries Service. October 15, 2009. Retrieved July 25, 2011.
  22. ^ Conaway, CH; Black, FJ; Grieb, TM; Roy, S; Flegal, AR (2008). Mercury in the San Francisco Estuary. Rev Environ Contam Toxicol. Reviews of Environmental Contamination and Toxicology. 194. pp. 29–54. doi:10.1007/978-0-387-74816-0_2. ISBN 9780387748153. PMID 18069645.
  23. ^ Bailey, Eric (November 9, 2007). "Oil oozes in S.F. Bay after ship hits bridge". Los Angeles Times. Archived from the original on March 22, 2019.
  24. ^ "Corkscrew Slough". Geographic Names Information System. United States Geological Survey.
  25. ^ Rebecca Sutton, Da Chen, Jennifer Sun, Denise J. Greig, and Yan Wu (2019). "Characterization of brominated, chlorinated, and phosphate flame retardants in San Francisco Bay, an urban estuary". Science of the Total Environment. 652: 212–223. Retrieved March 16, 2019.CS1 maint: Uses authors parameter (link)
  26. ^ Barnard, P. L.; Hanes, D. M.; Rubin, D. M.; Kvitek, R. G. (July 18, 2006). "Giant Sand Waves at the Mouth of San Francisco Bay" (PDF). Eos. 87 (29): 285, 289. Bibcode:2006EOSTr..87..285B. doi:10.1029/2006EO290003. Retrieved January 2, 2017.
  27. ^ Sandifur, Marilyn (September 18, 2009). "50 Feet Delivered!". Port of Oakland. Retrieved January 3, 2017.
  28. ^ United States. Army. Corps of Engineers. San Francisco District, Port of Oakland (1998). Oakland harbor navigation improvement (−50-foot) project: draft environmental impact statement/environmental impact report: executive summary. U.S. Army Corps of Engineers, San Francisco District.
  29. ^ "USA: Port of Oakland Secures USD 18 Million in Federal Funding for Dredging Project". Dredging Today. June 1, 2011. Retrieved March 22, 2012.
  30. ^ "USA: Congresswoman Helps Oakland Port Reach Major Funding Milestone for Deepening Project". Dredging Today. March 21, 2012. Retrieved March 22, 2012.
  31. ^ Matthews, Mark (March 22, 2012). "Huge container ship cruises into Port of Oakland". ABC7. San Francisco: KGO-TV/DT. Retrieved March 23, 2012.
  32. ^ Admin, OEHHA (December 30, 2014). "San Francisco Bay". OEHHA. Retrieved 13 June 2018.


External links

Alcatraz Island

Alcatraz Island () is located in San Francisco Bay, 1.25 miles (2.01 km) offshore from San Francisco, California, United States. The small island was developed with facilities for a lighthouse, a military fortification, a military prison (1828), and a federal prison from 1934 until 1963. Beginning in November 1969, the island was occupied for more than 19 months by a group of Native Americans from San Francisco, who were part of a wave of Native activism across the nation, with public protests through the 1970s. In 1972, Alcatraz became part of a national recreation area and received designation as a National Historic Landmark in 1986.

Today, the island's facilities are managed by the National Park Service as part of the Golden Gate National Recreation Area; it is open to tours. Visitors can reach the island in a little under 15 minutes by ferry ride from Pier 33, located between the San Francisco Ferry Building and Fisherman's Wharf, San Francisco. Hornblower Cruises and Events, operating under the name Alcatraz Cruises, is the official ferry provider to and from the island.

Alcatraz Island is home to the abandoned prison, the site of the oldest operating lighthouse on the West Coast of the United States, early military fortifications, and natural features such as rock pools and a seabird colony (mostly western gulls, cormorants, and egrets). According to a 1971 documentary on the history of Alcatraz, the island measures 1,675 feet (511 m) by 590 feet (180 m) and is 135 feet (41 m) at highest point during mean tide. The total area of the island is reported to be 22 acres (8.9 ha).Landmarks on the island include the Main Cellhouse, Dining Hall, Library, Lighthouse, the ruins of the Warden's House and Officers' Club, Parade Grounds, Building 64, Water Tower, New Industries Building, Model Industries Building,

and the Recreation Yard.

Don Edwards San Francisco Bay National Wildlife Refuge

Don Edwards San Francisco Bay National Wildlife Refuge (DESFBNWR) is a United States National Wildlife Refuge located in the southern part of San Francisco Bay, California. The Refuge headquarters and visitor center is located in the Baylands district of Fremont, next to Coyote Hills Regional Park, in Alameda County. The visitor center is on Marshlands Rd, off Thornton Ave.Most of the refuge stretches along the marshy shoreline north and south of the Dumbarton Bridge, but Bair Island, in San Mateo County, is also part of the system. The southernmost extent of the refuge is in northern Santa Clara County.


Earl Stevens (born November 15, 1967), better known by his stage name E-40, is an American rapper and actor. He is a founding member of the rap group The Click, and the founder of Sick Wid It Records. He has released twenty-seven studio albums to date, appeared on numerous movie soundtracks, and has also done guest appearances on a host of other rap albums. Initially an underground artist, his 1995 solo album In a Major Way opened him up to a wider audience. Beginning in 1998, he began collaborating with more mainstream rappers outside the Bay Area. He rose to even higher mainstream popularity in 2006 with his single "Tell Me When to Go" which was produced by Lil Jon.

East Bay (San Francisco Bay Area)

The eastern region of the San Francisco Bay Area, commonly referred to as the East Bay, includes cities along the eastern shores of the San Francisco Bay and San Pablo Bay. The region has grown to include inland communities in Alameda and Contra Costa Counties. With a population of roughly 2.5 million in 2010, it is the most populous subregion in the Bay Area.Oakland is the largest city in the East Bay and the third largest in the Bay Area. The city serves as a major transportation hub for the U.S. West Coast, and its port is the largest in Northern California. Increased population has led to the growth of large edge cities such as Alameda, Emeryville, Fremont, Pleasanton, San Ramon and Walnut Creek.

Eden Landing Ecological Reserve

Eden Landing Ecological Reserve is a nature reserve in Hayward and Union City, California, on the eastern shore of San Francisco Bay. The reserve is managed by the California Department of Fish and Game and comprises 5,040 acres of former industrial salt ponds now used as a low salinity waterbird habitat. It lies between the Hayward Regional Shoreline and Alameda Creek Regional Trail to the north and adjacent to Don Edwards National Wildlife Refuge and Coyote Hills Regional Park to the south and is south and adjacent to the San Mateo–Hayward Bridge, across which lies the Hayward Shoreline Interpretive Center. Some waterfowl hunting is periodically permitted. The remains of the Oliver Salt Company are located in the reserve.

This is part of the organization's South Bay Salt Ponds Restoration Project, which is the largest salt pond restoration project on the west coast of the United States. To date, over 1,000 acres of marsh have been restored, many of the former salt ponds have been enhanced for wildlife, and new trails and a kayak launch were opened to the public in April 2016. The Bay Area environmental organization Save the Bay is also working on the site to plant native vegetation along the edges of the salt marshes.

Grizzly Bay

Grizzly Bay is a baylet of the San Francisco Bay which dips into Solano County, California and borders Suisun Bay. Grizzly Bay is home to many sloughs and wildlife areas in addition to the Fifth Reserve Fleet which is docked off the coast of Benicia.

Suisun Slough and Cordelia Slough empty into Grizzly Bay.

North Bay (San Francisco Bay Area)

The North Bay is a subregion of the San Francisco Bay Area, in California, United States. The largest city is Santa Rosa, which is the fifth-largest city in the Bay Area. It is the location of the Napa and Sonoma wine regions, and is the least populous and least urbanized part of the Bay Area. It consists of Marin, Napa, Solano and Sonoma counties.

Richmond Inner Harbor

Richmond Inner Harbor is a deepwater body of water in Richmond, California. The harbor lies between Ferry Point and Point Isabel, between the mainland and Brooks Island in western Contra Costa County along the East Bay's northern East Shore. The harbor provides excellent protection as it lies protected by Brooks Island an extensive breakwater inside the already protected San Francisco Bay. The harbour connects to the Sante Fe Channel and its chanellets in addition to the Richmond Marina Bay and Campus Bay. Baxter Creek and Meeker Slough Creek's mouths and deltas drain into the harbor.

San Francisco Bay Area

San Francisco Bay Area (popularly referred to as the Bay Area) is a populous region surrounding the San Francisco, San Pablo and Suisun Bay estuaries in the northern part of the U.S. state of California. Although the exact boundaries of the region vary depending on the source, the Bay Area is generally accepted to include the nine counties that border the aforementioned estuaries: Alameda, Contra Costa, Marin, Napa, San Mateo, Santa Clara, Solano, Sonoma, and San Francisco. Other sources may exclude parts of or even entire counties, or expand the definition to include neighboring counties that don't border the bay such as San Benito, San Joaquin, and Santa Cruz.

Home to approximately 7.68 million people, Northern California's nine-county Bay Area contains many cities, towns, airports, and associated regional, state, and national parks, connected by a complex multimodal transportation network. The larger combined statistical area of the region, which includes twelve counties, is the second-largest in California (after the Greater Los Angeles area), the fifth-largest in the United States, and the 41st-largest urban area in the world with 8.75 million people. The Bay Area's population is ethnically diverse: for example, roughly half of the region's residents are Hispanic, Asian, African American, or Pacific Islander, all of whom have a significant presence throughout the region.

The earliest archaeological evidence of human settlements in the Bay Area dates back to 3000 BC. In 1769, the Bay Area was inhabited by the Ohlone people when a Spanish exploration party led by Gaspar de Portolà entered the Bay – the first documented European visit to the Bay Area. After Mexico established independence from Spain in 1821, the region was briefly controlled by the Mexican government until the United States purchased the territory in 1846 during the Mexican–American War. Soon after, discovery of gold in California attracted a flood of treasure seekers, many using ports in the Bay Area as an entry point. During the early years of California's statehood, state legislative business rotated between three locations in the Bay Area before a permanent state capital was established in Sacramento. A major earthquake leveled the city of San Francisco and environs in 1906, but the region quickly rebuilt in time to host the 1915 Panama-Pacific Exposition. During World War II, the Bay Area played a major role in America's war effort in the Asiatic-Pacific Theater, with San Francisco's Fort Mason acting as a primary embarkation point for American forces. In 1945, the United Nations Charter was signed in San Francisco, establishing the United Nations, and in 1951, the Treaty of San Francisco officially ended the U.S.'s war with Japan. Since then, the Bay Area has experienced numerous political, cultural and artistic movements, developing unique local genres in music and art and establishing itself as a hotbed of progressive politics. Economically, the post-war Bay Area saw huge growth in the financial and technology industries, creating a vibrant and diverse economy with a gross domestic product of over $800 billion, and home to the second highest concentration of Fortune 500 companies in the United States.

Despite its urban character, the San Francisco Bay is one of California's most ecologically important habitats, providing key ecosystem services such as filtering pollutants and sediments from the rivers, and supporting a number of endangered species. The region is also known for the complexity of its landforms, the result of millions of years of tectonic plate movements. Because the Bay Area is crossed by six major earthquake faults, the region is particularly exposed to hazards presented by large earthquakes. The climate is temperate and generally very mild, and is ideal for outdoor recreational and athletic activities such as hiking. The Bay Area is host to seven professional sports teams and is a cultural center for music, theater, and the arts. It is also host to several institutions of higher education, ranging from primary schools to major research universities. Home to 101 municipalities and nine counties, governance in the Bay Area is multifaceted and involves numerous local and regional actors, each with wide-ranging and overlapping responsibilities.

San Francisco Bay Ferry

San Francisco Bay Ferry is a public transit passenger ferry service in the San Francisco Bay, administered by the San Francisco Bay Area Water Emergency Transportation Authority (WETA). San Francisco Bay Ferry is a different system from Golden Gate Ferry, which provides passenger ferry service from San Francisco to Marin County.

San Francisco Bay Guardian

The San Francisco Bay Guardian was a free alternative newspaper published weekly in San Francisco, California. It was founded in 1966 by Bruce B. Brugmann and his wife, Jean Dibble. The paper was shut down on October 14, 2014. It was relaunched in February 2016 as an online publication.

The Bay Guardian was known for reporting, celebrating, and promoting left-wing and progressive issues within San Francisco and (albeit rarely) around the San Francisco Bay Area as a whole. This usually included muckraking, legislation to control and limit gentrification, and endorsement of political candidates and other laws and policies that fall within its political views. It also printed movie and music reviews, an annual nude beaches issue, and an annual sex issue. The Bay Guardian was one of several alternative newspapers in the greater San Francisco Bay Area, including SF Weekly (formerly its major competitor, now under the same ownership), East Bay Express, Metro Silicon Valley, North Bay Bohemian, Marin's Pacific Sun, and Berkeley Daily Planet.

San Francisco Bay National Estuarine Research Reserve

The San Francisco Bay National Estuarine Research Reserve (San Francisco Bay NERR) is one of 27 reserves established as part of the United States National Estuarine Research Reserve System. The reserve is used to promote San Francisco Bay wetlands and estuary research, education, and stewardship.

San Francisco Bay Trail

The San Francisco Bay Trail is a bicycle and pedestrian trail that will eventually allow continuous travel around the shoreline of San Francisco Bay. As of 2019, 356 miles (573 km) of trail have been completed. When finished, the Bay Trail will extend over 500 miles (805 km) to link the shoreline of nine counties, passing through 47 cities and crossing seven toll bridges. It is a project of the Association of Bay Area Governments (ABAG) and the Metropolitan Transportation Commission (San Francisco Bay Area) (MTC).

The Bay Trail is a collaboration between elected officials, government agencies, private companies, non-profit organizations, advocacy groups and the public to increase access to the edge of the bay. It provides recreational opportunities for hikers and bicyclists; offers a setting for wildlife viewing and environmental education; and serves as a bicycle transportation corridor. The Bay Trail provides access to points of historic, natural and cultural interest, and to numerous recreational areas, including over 130 parks. The Bay Trail consists of paved paths, gravel trails, bike lanes or sidewalks.

San Francisco Peninsula

The San Francisco Peninsula is a peninsula in the San Francisco Bay Area that separates San Francisco Bay from the Pacific Ocean. On its northern tip is the City and County of San Francisco. Its southern base is in northern Santa Clara County, including the cities of Palo Alto, Mountain View, and Los Altos. Most of the Peninsula is occupied by San Mateo County, between San Francisco and Santa Clara counties, and including the cities and towns of Atherton, Belmont, Brisbane, Burlingame, Colma, Daly City, East Palo Alto, El Granada, Foster City, Hillsborough, Half Moon Bay, La Honda, Loma Mar, Los Altos, Menlo Park, Millbrae, Mountain View, Pacifica, Palo Alto, Pescadero, Portola Valley, Redwood City, San Bruno, San Carlos, San Mateo, South San Francisco, Sunnyvale, and Woodside.

Whereas the term peninsula technically refers to the entire geographical San Franciscan Peninsula, in local jargon, "The Peninsula" does not include the city of San Francisco.

San Francisco–Oakland Bay Bridge

The San Francisco–Oakland Bay Bridge, known locally as the Bay Bridge, is a complex of bridges spanning San Francisco Bay in California. As part of Interstate 80 and the direct road between San Francisco and Oakland, it carries about 260,000 vehicles a day on its two decks. It has one of the longest spans in the United States.

The toll bridge was conceived as early as the gold rush days, but construction did not begin until 1933. Designed by Charles H. Purcell, and built by American Bridge Company, it opened on November 12, 1936, six months before the Golden Gate Bridge. It originally carried automobile traffic on its upper deck, and trucks and commuter trains on the lower, but after the Key System abandoned rail service, the lower deck was converted to all-road traffic as well. In 1986 the bridge was unofficially dedicated to James Rolph.The bridge has two sections of roughly equal length; the older western section, officially known as the Willie L. Brown Jr. Bridge (after former San Francisco Mayor and California State Assembly Speaker Willie L. Brown Jr.), connects downtown San Francisco to Yerba Buena Island, and the newer unnamed eastern section connects the island to Oakland. The western section is a double suspension bridge with two decks, westbound traffic being carried on the upper deck while eastbound is carried on the lower one. The largest span of the original eastern section was a cantilever bridge. During the 1989 Loma Prieta earthquake, a portion of the eastern section's upper deck collapsed onto the lower deck and the bridge was closed for a month. Reconstruction of the eastern section of the bridge as a causeway connected to a self-anchored suspension bridge began in 2002; the new eastern section opened September 2, 2013, at a reported cost of over $6.5 billion, a 2,500% cost overrun from the original estimate of $250 million. Unlike the western section and the original eastern section of the bridge, the new eastern section is a single deck with the eastbound and westbound lanes on each side making it the world's widest bridge, according to Guinness World Records, as of 2014. Demolition of the old east span was completed on September 8, 2018.

San Jose–San Francisco–Oakland, CA Combined Statistical Area

The San Jose–San Francisco–Oakland, CA Combined Statistical Area is a 12-county Combined Statistical Area (CSA) designated by the United States Office of Management and Budget in Northern California that includes the San Francisco Bay Area. The CSA is more extensive than the popular local definition of the Bay Area, which consists of only the nine counties bordering San Francisco and San Pablo Bays: Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano, and Sonoma. This group of counties also elects boards for regional planning and air quality control regulation. The CSA includes San Joaquin, Santa Cruz, and San Benito counties, which do not directly border the San Francisco or San Pablo bays, but are economically connected to the other nine counties that do.

The CSA ranks as the fifth most populous combined statistical area of the United States, and second in California.

San Pablo Bay

San Pablo Bay is a tidal estuary that forms the northern extension of San Francisco Bay in the East Bay and North Bay regions of the San Francisco Bay Area in northern California.

Most of the Bay is shallow; however, there is a deep water channel approximately in the middle of the bay, which allows access to major ports in Sacramento, Stockton, Benicia, and Martinez; and other smaller ports on the Sacramento–San Joaquin River Delta.

Suisun Bay

Suisun Bay ( sə-SOON) is a shallow tidal estuary (a northeastern extension of the San Francisco Bay) in northern California. It lies at the confluence of the Sacramento and San Joaquin Rivers, forming the entrance to the Sacramento–San Joaquin River Delta, an inverted river delta. Suisun Marsh, the tidal marsh land to the north, is the largest marsh in California. Grizzly Bay forms a northern extension of Suisun Bay. The bay is directly north of Contra Costa County.

The bay was named in 1811, after the Suisunes, a Native American tribe of the area. The word originates with the Patwin.

On the west, Suisun Bay is drained by the Carquinez Strait, which connects to San Pablo Bay, a northern extension of San Francisco Bay. In addition to the major bridges at the Carquinez Strait, it is spanned in its center by the Benicia-Martinez Bridge and at its eastern end by the State Route 160 crossing (Antioch Bridge) between Antioch and Oakley.

It is the anchorage of the Suisun Bay Reserve Fleet, a collection of U.S. Navy and merchant reserve ships, which was created in the period following World War II. The Glomar Explorer was anchored here after recovering parts of a sunken Soviet submarine in the mid-1970s (see Project Azorian). Many ships were removed and sold for scrap in the 1990s. In 2010, plans were announced to remove the mothball fleet in stages, with final removal by 2017.

The Central Pacific Railroad built a train ferry that operated between Benicia and Port Costa, California from 1879 to 1930. The ferry boats Solano and Contra Costa were removed from service when the nearby Martinez railroad bridge was completed in 1930. From 1913 until 1954 the Sacramento Northern Railway, an electrified interurban line, crossed Suisun Bay with the Ramon, a distillate-powered train ferry.

On April 28, 2004, a petroleum pipeline operated by Kinder Morgan Energy Partners ruptured, initially reported as spilling 1,500 barrels (264m³) of diesel fuel in the marshes, but, this was later updated to about 2,950 barrels. Kinder Morgan pleaded guilty to operating a corroded pipeline (and cited for failing to notify authorities quickly after the spill was discovered) and paid three million dollars in penalties and restitution.

Transportation in the San Francisco Bay Area

Transportation in the San Francisco Bay Area is reliant on a complex multimodal infrastructure consisting of roads, bridges, highways, rail, tunnels, airports, and bike and pedestrian paths. The development, maintenance, and operation of these different modes of transportation are overseen by various agencies, including the California Department of Transportation (Caltrans), the Association of Bay Area Governments, San Francisco Municipal Transportation Agency, and the Metropolitan Transportation Commission. These and other organizations collectively manage several interstate highways and state routes, two subway networks, two commuter rail agencies, eight trans-bay bridges, transbay ferry service, local bus service, three international airports, and an extensive network of roads, tunnels, and bike paths.

A 2011 Brookings Institution study ranked the San Francisco MSA and the San Jose MSA sixteenth and second, respectively, on transit coverage to job access. Another nationwide study, conducted by the University of Minnesota in 2014, ranked the San Francisco MSA second and San Jose MSA tenth. Despite this, the San Francisco Bay Area remains the second most traffic-congested region in the country with a declining per capita use of public transit.In 2013, the San Francisco-Oakland-Hayward metropolitan statistical area (San Francisco MSA) had the second lowest percentage of workers who commuted by private automobile (69.8 percent), with 7.6 percent of area workers traveling via bus. During the period starting in 2006 and ending in 2013, the San Francisco MSA had the greatest percentage decline of workers commuting by automobile (3.8 percent) among MSAs with more than a half million residents.

Bodies of water
Major cities
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Cities and towns
Cities and towns
San Francisco Bay watershed
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protected areas
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