The San Francisco Bay Area, popularly referred to as the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bayestuaries in Northern California. Although the exact boundaries of the region are variously defined, the Bay Area is defined by the Association of Bay Area Governments to include the nine counties that border the aforementioned estuaries: Alameda, Contra Costa, Marin, Napa, San Mateo, Santa Clara, Solano, Sonoma, and San Francisco.