San Francisco Skyline From Marin County

San Francisco Bay, California, U.S.A.

San Francisco Skyline From Marin County

San Francisco Skyline From Marin County

San Francisco Bay is a shallow, productive estuary through which water draining from approximately forty percent of California, flowing in the Sacramento and San Joaquin rivers from the Sierra Nevada mountains, enters the Pacific Ocean. Specifically, both rivers flow into Suisun Bay, which flows 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. However, the entire group of interconnected bays is often referred to as “San Francisco Bay”.

San Francisco Skyline

San Francisco Skyline

San Francisco Bay is located in the U.S. state of California, surrounded by a contiguous region known as the San Francisco Bay Area (often simply “the Bay Area”), dominated by the large cities San Francisco, Oakland, and San Jose. The waterway entrance to San Francisco Bay from the Pacific Ocean is called the Golden Gate. Across the strait spans the Golden Gate Bridge.

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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. During the last ice age, the basin now filled by the bay was a large linear valley with small hills, similar to most of the valleys of the Coast Ranges. The rivers of the Central Valley ran out to sea through a canyon that is now the Golden Gate. As the great ice sheets melted, sea level rose 300 feet (91 m) over 4,000 years, and the valley filled with water from the Pacific, becoming a bay. The small hills became islands.

Alcatraz Island - San Francisco Bay

Alcatraz Island – San Francisco Bay

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 (370 m) high Sweeney Ridge, where he sighted San Francisco Bay. Portola 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. 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.   This famous bay was the center of American settlement in the Far West during the 19th century. From the 1820s onward, American presidents and expansionists coveted the bay as a great natural harbor in the Pacific. After many failed efforts to buy the bay and varying areas around it, the US Navy and Army seized the region from Mexico during the Mexican-American War (1845–1848).

San Francisco Bay from the Air

San Francisco Bay from the Air

On February 2, 1848 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. During the California gold rush of 1848-1850s, San Francisco Bay instantly became one of the world’s greatest seaports, dominating shipping and transportation in the American West until the last years of the 19th century. The bay’s regional importance became paramount when the First Transcontinental Railroad reached its western terminus in Alameda on September 6, 1869. The terminus was switched to the Oakland Long Wharf two months later on November 8, 1869.  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 8 million residents.

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