The Bay Area (more precisely, the San Francisco Bay Area) is a geographically diverse and expansive metropolitan region in northern California that is home to about 7 million people in cities such as San Francisco, Oakland, and San Jose. The Bay Area was formerly a center for Spanish missions and Gold Rush prospectors, but is today best recognized for its lifestyle, liberal politics, and high-tech economy (Silicon Valley).

The Bay Area consists of portions of nine counties: Marin, Sonoma, Napa, Solano, San Francisco, San Mateo, Contra Costa, Alameda, and Santa Clara. The Bay Area has no defined borders. The Peninsula is comprised of the counties of San Mateo and the northern portion of Santa Clara, whereas the East Bay consists of Contra Costa and Alameda. The southern portions of Sonoma and Napa counties are included in the Bay Area for the purposes of this book because their cultures and economy face the Bay. Depending on who you ask, Gilroy and Santa Cruz are either part of the Bay Area or the Central Valley/Central Coast to the east and south, respectively.