This is a timeline of the San Francisco Bay Area in California, events in the nine counties that border on the San Francisco Bay, and the bay itself.
An identical list of events, formatted differently, may be found here.
Prehistory
The San Andreas Fault (pictured) begins to form in the mid Cenozoic about 30 million years ago 9.5 million years ago, the Moraga Volcanics produces most of the lavas that underlie the East Bay ridges from present day Tilden Regional Park to Moraga During the Quaternary glaciation beginning 2.58 million years ago, the basin that will be filled by the bay is a large linear valley with small hills, similar to most of the valleys of the Coast Ranges. The rivers of the Central Valley run out to sea through a canyon that will become the Golden Gate. As the ice sheets melt, sea levels rise over the next 4,000 years, and the valley fills with water from the Pacific. Evidence of human occupation of California dates from at least 17,000 BCE. The Ohlone people (pictured) inhabit the Bay Area region as early as 6,000 years ago, with a 1770 estimated population of 10,000–20,000 The Coast Miwok inhabit the Sonoma region as early as 4,000 years ago, with a 1770 estimated population of 2,000 The Patwin people inhabit the northern Bay region as early as 1,500 years ago, with a 1770 estimated population of 12,000 The Bay Miwok inhabit the region that is now Contra Costa County, with a 1770 estimated population of approximately 1,700
16th century
In 1539, Juan Rodríguez Cabrillo lands on islands off the coast of California, and names them Farallones, Spanish for cliffs or small pointed islets On 13 November 1542, Juan Rodríguez Cabrillo sights a peninsula from his ship and names it "Cabo de Pinos", while missing the entrance to San Francisco Bay
Francis Drake lands at what is now known as Drakes Bay in 1579 (pictured), and claims the land for England, as New Albion
17th century
Despite numerous sailing vessels traveling along the coast, no ships discover the Golden Gate and the San Francisco Bay, due to factors such as fog and ships avoiding sailing close to shore
18th century
Las Californias is established in 1768 by New Spain, encompassing the Bay Area
Gaspar de Portolà arrives in the Bay Area in 1769
Mission San Francisco de Asís and El Presidio Real de San Francisco are founded in 1776 in Yerba Buena Baptisms of the Yelamu by Spanish missionaries begin in 1777 La Misión Santa Clara de Thamien and el Pueblo de San José de Guadalupe are established in 1777 on the Guadalupe River In 1786, Jean-François de Galaup, comte de Lapérouse sails to San Francisco and maps the Bay Area In 1792, British explorer George Vancouver stops in San Francisco, in part, according to his journal, to spy on the Spanish settlements in the area
19th century
In 1804, The Bay Area is part of the newly created New Spain state of Alta California The Russian-American Company establishes Fortress Ross (Крѣпость Россъ, tr. Krepostʹ Ross) (pictured) in 1812, in what is now Sonoma County In 1821, New Spain cedes Alta California, including the Bay Area, to the newly created Mexican Empire William A. Richardson (pictured) arrives in San Francisco in 1822, and in 1838 is given Rancho Saucelito in present-day Marin County by Mexican Governor Juan Alvarado In 1823, the Bay Area, as part of Alta California, becomes part of the newly founded United Mexican States In 1837, Antonio Ortega begins operating a pulqueria (tavern) north of San Francisco, on the former site of Mission San Francisco Solano In 1838, a 7.0 MLa earthquake strikes the Peninsula, on or near the San Andreas Fault, with a maximum Mercalli intensity of VIII (Severe)
Colonists in Alta California rebel against the Mexican department's government, raise a flag featuring a grizzly bear (pictured) at El Cuartel de Sonoma, and establish the short-lived (and unrecognized) California Republic US Navy Commodore John D. Sloat claims California for the United States during the Mexican–American War, and US Navy Captain John Berrien Montgomery and US Marine Second Lieutenant Henry Bulls Watson of the arrives to claim Yerba Buena two days later by raising the American flag over the town plaza Washington Allon Bartlett is named alcalde of Yerba Buena Yerba Buena doubles in population when about 240 Mormon pioneers arrive, among them Samuel Brannan