The United States has named the San Francisco Bay/Estuary (SFBE) (158,711 ha; 37°52’N 122°23’W) as its 35th Wetland of International Importance, effective on World Wetlands Day, 2 February 2013. The San Francisco Bay is the largest estuary on the Pacific Coast of the US, encompassing approximately 160,000 hectares, and it is widely recognized as one of North America’s most ecologically important estuaries, accounting for 77% of California’s remaining perennial estuarine wetlands and providing key habitat for a broad suite of flora and fauna and a range of ecological services such as flood protection, water quality maintenance, nutrient filtration and cycling, and carbon sequestration. The site is home to many plant species and over 1,000 species of animals, including endemic and conservation status species. It is noted for hosting more wintering shorebirds than any other estuary along the US Pacific Coast south of Alaska and is recognized as a site of Hemispheric Importance by the Western Hemisphere Shorebird Reserve Network. It is also important for over 130 species of resident and migratory marine, estuarine and anadromous fish species.
Development pressures on remaining wetlands and adjacent uplands continue to threaten habitats not owned or managed for conservation. The site is a renowned international tourism destination. Parts of the site are within the UNESCO Golden Gate Biosphere Reserve (1988), and it encompasses a number of US National Wildlife Refuges and other protected areas.