Where is Silicon Valley located?

Silicon Valley is an ever-expanding economic region that is located in Northern California and in the United States.

Forty to fifty years ago, Silicon Valley was a nickname for Santa Clara Valley. The Valley was the hub of the silicon chip industry with Fairchild Semiconductor in Mountain View as its center and hundreds of spin-offs from Fairchild, related service companies, and competitors. As the industry and economy grew with the price of real estate, the economic region of Silicon Valley began to expand. 

In 2021, one could argue that Silicon Valley companies stretch from Monterey to Santa Rosa and Santa Cruz to Grass Valley. Many high-tech companies within these expanding physical perimeters view themselves, their industries, and their locations as all part of the greater Silicon Valley region.

Located in the United States - in Northern California - originally Silicon Valley was within the boundaries of Santa Clara Valley, which stretched from Menlo Park in the north to San Jose in the south. Because Silicon Valley is an economic region, it now includes territory down to Monterey, north to Santa Rosa and east as far as Sacramento.

Cities in the region of Silicon Valley:

Alameda
Alameda is a city in Alameda County, California, United States. It is located on Alameda Island and Bay Farm Island, and is adjacent to and south of Oakland and east of San Francisco across the San Francisco Bay.

Atherton
Atherton is a small, rural, and residential community, with no industrial land-use base. Native live oaks, white oaks, bays, redwoods, cedars, pines, and other ornamental trees cover the six square miles of town.

Berkeley
Berkeley is a city on the east shore of San Francisco Bay in northern Alameda County, California.

Burlingame
Burlingame is a city in San Mateo County, California. It is located on the San Francisco Peninsula and has a significant shoreline on San Francisco Bay. 

Concord
Concord is the largest city in Contra Costa County, California. The city is a major regional suburban East Bay center within the San Francisco Bay Area, and is 29 miles (47 km) east of San Francisco.

Corte Madera
Corte Madera is an incorporated town in Marin County, California, United States. Corte Madera is located 3.25 miles (5.2 km) south of San Rafael,[9] at an elevation of 39 feet (12 m).

Cupertino
Cupertino is a U.S. city in Santa Clara County, California, directly west of San Jose on the western edge of the Santa Clara Valley with portions extending into the foothills of the Santa Cruz Mountains.

Daly City
Daly City is the largest city in San Mateo County, California, United States. Located immediately south of San Francisco, it is named in honor of businessman and landowner John Donald Daly.

Danville
The Town of Danville is located in the San Ramon Valley in Contra Costa County, California. It is one of the incorporated municipalities in California.

Davis
Davis, formerly known as Davisville, is a city in the U.S. state of California and the most populous city in Yolo County.

Dublin
Dublin is a suburban city of the East (San Francisco) Bay and Tri-Valley regions of Alameda County, California, United States. Located along the north side of Interstate 580 at the intersection with Interstate 680, roughly 35 miles (56 km) east of downtown San Francisco, 23 miles (37 km) east of downtown Oakland, and 31 miles (50 km) north of downtown San Jose, it was referred to as "Dublin" in reference to the city of Dublin in Ireland because of the large number of Irish who lived there.

East Palo Alto
East Palo Alto (abbreviated E.P.A.) is a city in San Mateo County, California, United States. It is situated on the San Francisco Peninsula, roughly halfway between the cities of San Francisco and San Jose. To the north and east is the San Francisco Bay, to the west is the city of Menlo Park, and to the south the city of Palo Alto. Despite being called "East" Palo Alto, this is a misnomer, as the city is precisely due north of Palo Alto. While often incorrectly assumed to be part of the city of Palo Alto,[4][5] East Palo Alto has always been a separate entity since its founding as an unincorporated community. It is also in San Mateo County, while Palo Alto is in Santa Clara County.

Emeryville
Emeryville is a small city located in northwest Alameda County, California, in the United States. It is located in a corridor between the cities of Berkeley and Oakland, extending to the shore of San Francisco Bay. 

Foster City
Foster City is a planned city located in San Mateo County, California. 

Fremont
Fremont is a city in Alameda County, California, United States. It was incorporated on January 23, 1956, from the annexing of Centerville, Niles, Irvington, Mission San José, and Warm Springs.

Gilroy
Gilroy is a city located in Northern California's Santa Clara County, south of Morgan Hill and north of San Benito County.

Hayward
Hayward is a city located in Alameda County, California in the East Bay subregion of the San Francisco Bay Area.

Hillsborough
Hillsborough is an incorporated town in San Mateo County, California, in the San Francisco Bay Area. It is located 17 miles (27 km) south of San Francisco on the San Francisco Peninsula, bordered by Burlingame to the north, San Mateo to the east, Highlands-Baywood Park to the south, and Interstate 280 to the west.

Los Altos
Los Altos is a city in Santa Clara County, California, in northern Silicon Valley, in the San Francisco Bay Area.

Los Gatos
Los Gatos is an incorporated town in Santa Clara County, California, United States.

Menlo Park
Menlo Park is a city at the eastern edge of San Mateo County, in the San Francisco Bay Area of California, in the United States. It is bordered by San Francisco Bay on the north and east; East Palo Alto, Palo Alto, and Stanford to the south; Atherton, North Fair Oaks, and Redwood City to the west.

Millbrae
Millbrae is a city in San Mateo County, California, United States, just west of San Francisco Bay, with San Bruno on the north and Burlingame on the south.

Milpitas
Milpitas is a city in Santa Clara County, California. It is located with San Jose to its south and Fremont to its north, at the eastern end of State Route 237 and generally between Interstates 680 and 880 which run roughly north/south through the city. With Alameda County bordering directly on the north, Milpitas sits in the extreme northeast section of the South Bay, bordering the East Bay and Fremont. Milpitas is also located within the Silicon Valley.

Monte Sereno
Monte Sereno is a city in Santa Clara County, California, USA. The city is located in the foothills of the Santa Cruz Mountains, about 10 miles (16 km) southwest of San Jose, immediately northwest of Los Gatos, and southeast of Saratoga.

Monterey
Monterey is a city located in Monterey County in the U.S. state of California, on the southern edge of Monterey Bay on California's Central Coast.

Moraga
Moraga (incorporating the former communities of Moraga Town, Rheem, and Rheem Valley) is a suburban incorporated town located in Contra Costa County, California, United States, in the San Francisco Bay Area.

Mountain View
Mountain View is a city located in Santa Clara County, California, United States. The city borders Palo Alto and the San Francisco Bay to the north, Los Altos to the south, and Moffett Federal Airfield and Sunnyvale to the east.

Newark
Newark is a city in Alameda County, California, United States. It was incorporated as a city in September 1955. Newark is an enclave, surrounded by the city of Fremont. The three cities of Newark, Fremont, and Union City make up the "Tri-City" area. 

Oakland
Oakland is the largest city and the county seat of Alameda County, California, United States. A major West Coast port city, Oakland is the largest city in the East Bay region of the San Francisco Bay Area.

Orinda
Orinda is a city in Contra Costa County, California, United States. The city is located just east of the city of Berkeley.

Palo Alto
Palo Alto is a charter city located in the northwest corner of Santa Clara County, California, in the San Francisco Bay Area of the United States. Palo Alto means tall tree in Spanish.

Pleasanton
Pleasanton is a city in Alameda County, California, incorporated in 1894. It is a suburb in the San Francisco Bay Area located about 25 miles (40 km) east of Oakland, and 6 miles (9.7 km) west of Livermore. 

Portola Valley
Portola Valley is an incorporated town in San Mateo County, California, United States, which was founded in 1964.

Redwood City
Redwood City is a city on the San Francisco Peninsula in Northern California's Bay Area, approximately 27 miles (43 km) south of San Francisco, and 24 miles (39 km) northwest of San Jose.

Redwood Shores
Redwood Shores is a waterfront community in Redwood City, California. It is located along the western shore of San Francisco Bay on the San Francisco Peninsula in San Mateo County.

Richmond
Richmond is a city in western Contra Costa County, California, United States. Located in the East Bay region of the San Francisco Bay Area, Richmond borders the cities of San Pablo, Albany, El Cerrito and Pinole in addition to the unincorporated communities of North Richmond, Hasford Heights, Kensington, El Sobrante, Bayview-Montalvin Manor, Tara Hills, and East Richmond Heights, and for a short distance San Francisco on Red Rock Island in the San Francisco Bay.

San Bruno
San Bruno is a city in San Mateo County, California, United States, incorporated in 1914. The city is located between South San Francisco and Millbrae, adjacent to San Francisco International Airport and Golden Gate National Cemetery, and is approximately 12 miles (19 km) south of downtown San Francisco.

San Francisco
San Francisco officially the City and County of San Francisco, is the cultural, commercial, and financial center of Northern California. It covers an area of about 46.89 square miles (121.4 km2), mostly at the north end of the San Francisco Peninsula in the San Francisco Bay Area.

San Jose
San Jose is an economic, cultural, and political center of Silicon Valley and the largest city in Northern California. Located in the center of the Santa Clara Valley, on the southern shore of San Francisco Bay, San Jose covers an area of 179.97 square miles (466.1 km2). San Jose is the county seat of Santa Clara County, the most affluent county in California and one of the most affluent counties in the United States.

San Leandro
San Leandro is a large suburban town in Alameda County, California, United States. It is located on the eastern shore of San Francisco Bay, between Oakland to the northwest and Hayward to the southeast.

San Mateo
San Mateo is a city in San Mateo County, California, located in the high-tech enclave of Silicon Valley in the San Francisco Bay Area. San Mateo is located between Burlingame to the north, Foster City and San Francisco Bay to the east, Belmont to the south, and Highlands-Baywood Park and Hillsborough to the west.

San Rafael
San Rafael is a city and the county seat of Marin County, California, United States.

San Ramon
San Ramon is a city in Contra Costa County, California, United States, located 34 miles east of San Francisco, and within the San Ramon Valley.

Santa Clara
Santa Clara is a city in Santa Clara County, California. Located 45 miles (72 km) southeast of San Francisco, the city was founded in 1777 with the establishment of Mission Santa Clara de Asís, the eighth of 21 California missions. 

Santa Cruz
Santa Cruz is the county seat and largest city of Santa Cruz County, California. Situated on the northern edge of Monterey Bay, about 32 mi (51 km) south of San Jose and 75 mi (120 km) south of San Francisco, the city is part of the 12-county San Jose-San Francisco-Oakland Combined Statistical Area.

Saratoga
Saratoga is a city in Santa Clara County, California, United States. It is located on the west side of the Santa Clara Valley, directly west of San Jose, in the San Francisco Bay Area. 

Sausalito
Sausalito is a city in Marin County, California, located 8 miles (13 km) south-southeast of San Rafael,[9] 4 miles (7 km) north of San Francisco.

Scotts Valley
Scotts Valley is a small city in Santa Cruz County, California, United States, about thirty miles (48 km) south of downtown San Jose and six miles (10 km) north of the city of Santa Cruz, in the upland slope of the Santa Cruz Mountains. Principal access to the city is supplied by State Route 17that connects San Jose and Santa Cruz. The city was incorporated in 1966. Scotts Valley is named for John Scott, who discovered gold at Scott’s Bar.

South San Francisco
South San Francisco is a city in San Mateo County, California, United States, located on the San Francisco Peninsula in the San Francisco Bay Area. 

Stanford
Stanford is a census-designated place (CDP) in Santa Clara County, California, United States and is the home of Stanford University.

Sunnyvale
Sunnyvale is a city located in Santa Clara County, California. It is bordered by portions of San Jose to the north, Moffett Federal Airfield to the northwest, Mountain View to the west, Los Altos to the southwest, Cupertino to the south, and Santa Clara to the east. It lies along the historic El Camino Real and Highway 101.

Walnut Creek
Walnut Creek is a city in Contra Costa County, California, United States, located in the East Bay region of the San Francisco Bay Area, about 16 miles (26 kilometers) east of the city of Oakland. 

Woodside
Woodside is a small incorporated town in San Mateo County, California, United States, on the San Francisco Peninsula.