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San Francisco Bay
The great natural harbor of Northern California
San Francisco Bay is the large, sheltered estuary that nearly cuts Northern California in two, draining the Sacramento and San Joaquin rivers - and with them the runoff of most of the Central Valley and the Sierra Nevada - out to the Pacific through the narrow strait spanned by the Golden Gate Bridge. One of the world's great natural harbors, it was hidden from European ships for two centuries behind that fog-shrouded gap in the coast.
The bay is the heart of one of the country's largest metropolitan regions, ringed by San Francisco, Oakland, and the cities of Silicon Valley. Mostly shallow, it has lost much of its historic tidal marsh to a century of diking and filling, prompting major restoration efforts. Its waters, wetlands, and the dramatic landscape around the Golden Gate make it one of the most recognizable estuaries in America.