San Francisco Bay: Quick Facts

Written and fact-checked by

The Information Architects of Encyclopaedia Britannica

Last updated

Nov. 1, 2026

News •

UPDATE: Coastal flood advisory issued for Northern California until Sunday evening • Oct. 23, 2026, 3:50 PM ET (The Sacramento Bee)

These California highways are most at risk of flooding during El Niño storms • Oct. 22, 2026, 7:15 PM ET (San Francisco Chronicle)

Photos

The Golden Gate Bridge spans the entrance to San Francisco Bay, with its tall red towers and suspension cables rising above the water and hills in the background.

Alcatraz Island

San Francisco Bay

Aerial view of the Golden Gate Bridge stretching across the bay toward hills in San Francisco, California, with cars visible on the bridge and water below.

Historical map of the San Francisco Bay area around 1900, showing the city of San Francisco and surrounding regions including Marin, Alameda, Contra Costa, and Solano counties. The map details coastlines, waterways, and key cities, with urban areas shaded and major roads and railways indicated.

See All Images →

Topics

Puget Sound Gulf of Alaska Ha Long Bay Port Jackson Botany Bay Milford Sound Gulf of California Port Arthur Gulf of Tonkin Prince William Sound

water glass on white background. (drink; clear; clean water; liquid)

Water and its Varying Forms