San Francisco Bay, 50 mi (80 km) long and from 3 to 13 mi (4.8–21 km) wide, W Calif.; entered through the Golden Gate, a strait between two peninsulas. The bay is as deep as 100 ft (30 m) in spots, with a channel 50 ft (15 m) deep maintained through the sandbar off the Golden Gate. San Francisco is on the southern peninsula; on the northern peninsula are the residential suburbs of Marin co., while on the eastern shore of the crescent-shaped bay are such industrial cities as Alameda, Oakland, Berkeley, and Richmond. The Santa Clara Valley, part of a great depression paralleling the coast, is the landward extension of the bay. Angel Island, Alcatraz, and Yerba Buena Island are in the bay. With San Pablo Bay and Suisun Bay, the natural harbor of San Francisco Bay is one of the best in the world. On those secondary bays and on Carquinez Strait, which connects them, are the cities of Vallejo, Benicia, Martinez, and Pittsburg. The Bay Area is served by a network of bridges, most important of which are the Golden Gate Bridge, the San Francisco–Oakland Bay Bridge, the Richmond–San Rafael Bridge, and the San Mateo Bridge. The Trans-Bay Tube, a tunnel 3.5 mi (5.6 km) long between San Francisco and Oakland, is one of the longest underwater rapid transit tubes in the world. The tunnel was especially constructed to absorb earthquake tremors. Several U.S. navy facilities are located in the region. The English navigator Sir Francis Drake Drake, Sir Francis, 1540?–1596, English navigator and admiral, first Englishman to circumnavigate the world (1577–80).

Early Career

He was born in Devonshire, the son of a yeoman, and was at an early age apprenticed to a ship captain.
..... Click the link for more information. visited the bay in 1579; the Spanish explored it more fully in the late 18th cent.

San Francisco Bay

Large, nearly landlocked bay indenting west-central California, U.S. A drowned river valley paralleling the coastline, it is connected with the Pacific Ocean by the Golden Gate Strait, which is spanned by the Golden Gate Bridge. The bay is one of the world's finest natural harbours. Treasure, Yerba Buena, Angel, and Alcatraz islands are there; the cities of San Francisco, Oakland, and Berkeley are nearby.

San Francisco Bay

an inlet of the Pacific in W California, linked with the open sea by the Golden Gate strait. Length: about 80 km (50 miles). Greatest width: 19 km (12 miles)