The San Francisco Bay Area, also known as the Bay Area, is a geographically diverse metropolitan area that surrounds the San Francisco Bay in Northern California. Home to more than eight million people, it is composed of cities, towns, military bases, airports, and associated regional, state, and national parks sprawled over nine counties (ten, according to some agencies) and connected by a massive network of roads, highways, railroads, and commuter rail.
The Bay Area, unlike the typical metropolitan area, contains several distinct urban and suburban centers. While San Jose is the largest city in the Bay Area (having surpassed San Francisco in the 1990 census), for most of its history San Francisco was the largest city in the region. The area containing the city of San Francisco, together with Oakland and San Jose, is the sixth-largest consolidated metropolitan area in the United States.The following lists are based on the ten-county definition of the Bay Area. Cities in bold serve as county seat. The places listed in italics are located in Santa Cruz county, which is excluded by the nine-county definition.

Counties
* Alameda County
* Contra Costa County
* Marin County
* Napa County
* San Francisco County
* San Mateo County
* Santa Clara County
* Santa Cruz County
* Solano County
* Sonoma County

Cities with more than 200,000 inhabitants
* San Jose, 953,679
* San Francisco, 799,263
* Oakland, 412,318
* Fremont, 210,158

Cities with 100,000 to 200,000 inhabitants
* Antioch
* Berkeley
* Concord
* Daly City
* Fairfield
* Hayward
* Richmond
* Santa Clara
* Santa Rosa
* Sunnyvale
* Vallejo

Municipalities and suburbs with 10,000 to 100,000 inhabitants
* Alameda
* Alamo
* Albany
* American Canyon
* Ashland
* Bay Point
* Belmont
* Benicia
* Blackhawk-Camino Tassajara
* Brentwood
* Burlingame
* Campbell
* Capitola
* Castro Valley
* Cherryland
* Clayton
* Cupertino
* Danville
* Dixon
* Dublin
* East Palo Alto
* El Cerrito
* El Sobrante
* Foster City
* Gilroy
* Half Moon Bay
* Healdsburg
* Hercules
* Hillsborough
* Lafayette
* Larkspur
* Live Oak
* Livermore
* Los Altos
* Los Gatos
* Martinez
* Menlo Park
* Mill Valley
* Millbrae
* Milpitas
* Moraga
* Morgan Hill
* Mountain View (Santa Clara Co.)
* Napa
* Newark
* Novato
* Oakley
* Orinda
* Pacifica
* Palo Alto
* Petaluma
* Piedmont
* Pinole
* Pittsburg
* Pleasant Hill
* Pleasanton
* Redwood City
* Rohnert Park
* San Anselmo
* San Bruno
* San Carlos
* San Leandro
* San Lorenzo
* San Mateo
* San Pablo
* San Rafael
* San Ramon
* Santa Cruz
* Saratoga
* Scotts Valley
* South San Francisco
* Stanford
* Suisun City
* Tamalpais-Homestead Valley
* Union City
* Vacaville
* Walnut Creek
* Watsonville
* Windsor

Municipalities and suburbs with fewer than 10,000 inhabitants
* Amesti
* Angwin
* Aptos
* Aptos Hills-Larkin Valley
* Atherton
* Bayview-Montalvin
* Belvedere
* Ben Lomond
* Bethel Island
* Black Point-Green Point
* Bodega Bay
* Bolinas
* Bonny Doon
* Boyes Hot Springs
* Boulder Creek
* Brisbane
* Broadmoor
* Buena Vista
* Burbank
* Byron
* Calistoga
* Cloverdale
* Clyde
* Colma
* Corralitos
* Corte Madera
* Cotati
* Crockett
* Day Valley
* Deer Park
* Diablo
* Dillon Beach
* Discovery Bay
* East Richmond Heights
* East Foothills
* El Granada
* El Verano
* Eldridge
* Elmira
* Emeryville
* Fairfax
* Fairview
* Felton
* Fetters Hot Springs-Agua Caliente
* Forestville
* Freedom
* Fruitdale
* Glen Ellen
* Graton
* Green Valley
* Guerneville
* Highlands-Baywood Park
* Interlaken
* Inverness
* Kensington
* Kentfield
* Kenwood
* Knightsen
* La Honda
* Lagunitas-Forest Knolls
* Larkfield-Wikiup
* Lexington Hills
* Loma Mar
* Los Altos Hills
* Loyola
* Lucas Valley-Marinwood
* Montara
* Monte Rio
* Monte Sereno
* Moss Beach
* Mount Eden
* Mount Hermon
* Mountain View, Contra Costa Co.
* Muir Beach
* Occidental
* Opal Cliffs
* Pacheco
* Pescadero
* Point Reyes Station
* Port Costa
* Portola Valley
* Rio del Mar
* Rio Vista
* Rodeo
* Rollingwood
* Roseland
* Ross
* Saint Helena
* San Geronimo
* San Gregorio
* San Martin
* Santa Venetia
* Sausalito
* Sebastopol
* Seven Trees
* Sonoma
* Soquel
* Stinson Beach
* Strawberry
* Sunol
* Sunol-Midtown
* Tara Hills
* Temelec
* Tiburon
* Tomales
* Twin Lakes
* Vine Hill
* Waldon
* West Menlo Park
* Woodacre
* Woodside
* Yountville