San Francisco Bay Area

San Francisco Bay Area
A montage of eight pictures of different locations in the Bay Area
Clockwise from top: The Stanford University Oval, San Francisco Chinatown with the Bay Bridge in the background, Napa Valley vineyards, the Circle of Palms Plaza in San Jose, the Golden Gate Bridge, the Palo Alto Baylands Nature Preserve, Oakland's downtown skyline, and redwood trees in Muir Woods
Location of the Bay Area within California.      The nine-county Bay Area.      Additional counties in the larger twelve-county CSA.
Location of the Bay Area within California.
     The nine-county Bay Area.
     Additional counties in the larger twelve-county CSA.
Country United States
State California
Subregions
Principal cities
Area
 • Nine-county6,966 sq mi (18,040 km2)
 • CSA10,191 sq mi (26,390 km2)
Highest elevation4,360 ft (1,330 m)
Lowest elevation−13 ft (−4 m)
Population
(2018)
 • Nine-county
7.77 million[4]
 • Nine-county density1,102.5/sq mi (425.7/km2)
 • CSA
8.84 million[5]
 • CSA density859/sq mi (332/km2)
Time zoneUTC−08:00 (Pacific)
 • Summer (DST)UTC−07:00 (PDT)
Area codes408/669, 415/628, 510/341, 650, 707, 925[6]

The San Francisco Bay Area (popularly referred to as the Bay Area) is a populous region surrounding the San Francisco, San Pablo and Suisun 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.[7] 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.

Boundaries

A map demarcating the boundaries of the nine-county Bay Area and the five subregions within.
A map of the locally accepted nine-county definition of the Bay Area. Also displayed are the five subregions of the Bay Area, which are divided along county lines except for the northwestern portion of Santa Clara county.

The borders of the San Francisco Bay Area are not officially delineated, and the unique development patterns influenced by the region's topography, along with the presence of unusual commute patterns caused by the presence of three central cities and employment centers located in various suburban locales, has led to considerable disagreement between local and federal definitions of the area.[8] Because of this, professor of geography at the University of California, Berkeley Richard Walker claimed that "no other U.S. city-region is as definitionally challenged [as the Bay Area]."[8]

When the region began to rapidly develop during and immediately after World War II, local planners settled on a nine-county definition for the Bay Area, consisting of the counties that directly border the San Francisco, San Pablo, and Suisun estuaries: Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano, and Sonoma counties.[9] Today, this definition is accepted by most local governmental agencies including San Francisco Regional Water Quality Control Board,[10] Bay Area Air Quality Management District,[11] the San Francisco Bay Restoration Authority,[12] the Metropolitan Transportation Commission,[13] and the Association of Bay Area Governments,[14] the latter two of which partner to deliver a Bay Area Census using the nine-county definition.[15]

Various U.S. Federal government agencies use definitions that differ from their local counterparts' nine-county definition. For example, the Federal Communications Commission (FCC) which regulates broadcast, cable, and satellite transmissions, includes nearby Colusa, Lake and Mendocino counties in their "San Francisco-Oakland-San Jose" media market, but excludes eastern Solano county.[16] On the other hand, the United States Office of Management and Budget, which designates Metropolitan Statistical Areas (MSAs) and Combined Statistical Areas (CSA) for populated regions across the country, has five MSAs which include, wholly or partially, areas within the nine-county definition, and one CSA which includes all nine counties plus neighboring San Benito, Santa Cruz and San Joaquin counties.[17]

Subregions

Among locals, the nine-county Bay Area can be further divided into five sub-regions: the East Bay, North Bay, South Bay, Peninsula, and the city of San Francisco. Although geographically located on the tip of the San Francisco Peninsula, the city of San Francisco is not considered part of the "Peninsula" subregion, but as a separate entity.[18][19]

The "East Bay" is the densest region of the Bay Area outside of San Francisco and includes cities and towns in Alameda and Contra Costa counties, centered around Oakland. As one of the larger subregions, the East Bay includes a variety of enclaves, including the suburban Tri-Valley area and the highly urban western part of the subregion that runs alongside the bay.[20] The "Peninsula" subregion includes the cities and towns on the San Francisco Peninsula, excluding the titular city of San Francisco. Its eastern half, which runs alongside the Bay, is highly populated while its less populated western coast traces the coastline of the Pacific Ocean and is known for its open space and hiking trails. Roughly coinciding with the borders of San Mateo county, it also includes the northwestern Santa Clara county cities of Palo Alto, Mountain View, and Los Altos.[21] The "South Bay" includes all of the rest of the cities in Santa Clara county, centered around San Jose, the largest city in Northern California.[22] It is roughly synonymous with Silicon Valley due to its high concentration of tech companies, although the industry also has a significant presence in the rest of the Bay Area.[23] The "North Bay" includes Marin, Sonoma, Napa, and Solano counties, and is the largest and least populated subregion. The western counties of Marin and Sonoma are encased by the Pacific Ocean on the west and the bay on the east, and are characterized by its mountainous and woody terrain. Sonoma and Napa counties are known internationally for their grape vineyards and wineries, and Solano county to the east, centered around Vallejo, is the fastest growing region in the Bay Area.[24]

Other Languages
Bahasa Indonesia: Wilayah Teluk San Francisco
Bahasa Melayu: San Francisco Bay Area
Simple English: San Francisco Bay Area
српски / srpski: Zalivska oblast San Franciska
srpskohrvatski / српскохрватски: San Francisco Bay Area