The California Bay Area is a large metropolitan region with several major cities. These are the 12 most prominent ones: San Francisco, Oakland, San Jose, Berkeley, Fremont, Hayward, Santa Clara, Sunnyvale, Mountain View, Redwood City, Palo Alto, and Walnut Creek. These cities represent a mix of urban, suburban, and tech-focused hubs, with San Francisco, San Jose, and Oakland being the largest and most influential in the region.