The Bay Area is a region in Northern California that includes the cities of Berkeley, Alameda, Oakland, and San Mateo. Berkeley is a city located in the East Bay region of the Bay Area, known for its liberal politics and being home to the University of California, Berkeley. Alameda is an island city located in the San Francisco Bay, connected to Oakland by bridges. Oakland is the largest city in the Bay Area and is known for its diverse population and vibrant culture. San Mateo is a city located in the Peninsula region of the Bay Area, known for its mild climate and proximity to Silicon Valley.