Transportation
San Francisco Bay was traversed by watercraft since before the coming of Europeans; the indigenous peoples used their canoes to fish and clam along the shoreline. The era of sail brought ships that communicated with the rest of the world and served as early ferries and freighters within the Bay and between the Bay and inland ports such as Sacramento and Stockton. These were gradually replaced by steam-powered vessels starting in the late 19th century. Several shipyards were early established around the Bay, augmented during wartime. (See e.g. Kaiser Shipyards)
San Francisco Bay is spanned by eight bridges, all of them dedicated to vehicle traffic: the Golden Gate Bridge on Highway 101 (which was the largest single span suspension bridge ever built at the time of its construction) which connects San Francisco and Marin counties and is the only bridge in the area not owned by the State of California. The Richmond-San Rafael Bridge on Interstate 580 which connects Marin and Contra Costa counties, the San Francisco – Oakland Bay Bridge on Interstate 80 which connects Alameda and San Francisco counties, the Hayward-San Mateo Bridge on Highway 92 which connects Alameda and San Mateo counties and the Dumbarton Bridge on Highway 84 which connects Alameda and San Mateo counties. The Carquinez Bridge on Interstate 80, the Benicia Bridge on Interstate 680 and the Antioch Bridge on Highway 160 all connect Contra Costa and Solano county. The bay is also spanned by the Transbay Tube, an underwater tube through which BART runs. Prior to the construction of these infrastructures, transbay transportation was dominated by fleets of ferryboats operated by the Southern Pacific Railroad and the Key System transit company. However, in recent decades, ferries have returned, primarily serving commuters from Marin County, relieving the traffic bottleneck of the Golden Gate Bridge. (See article Ferries of San Francisco Bay).
The Bay also continues to serve as a major international shipping port, served by a large container facility operated by the Port of Oakland, and two smaller facilities in Richmond and San Francisco.
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