The San Francisco Bay Area, commonly known as the Bay Area, is a metropolitan region that surrounds the San Francisco and San Pablo estuaries in Northern California. The region encompasses metropolitan areas such as San Francisco-Oakland (12th largest in the country), San Jose (31st largest in the country), along with smaller urban and rural areas. Overall, the Bay Area consists of nine counties, 101 cities, and 7,000 square miles. The nine counties are Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano, and Sonoma.
The Bay Area is home to many well-known cities. San Francisco is famous for its steep hills, cable cars and historic streetcars, the Golden Gate Bridge, and Fisherman's Wharf. Oakland, on the east side of the bay, has the fifth largest container shipping port in the United States. The city is also a major rail terminus. San Jose sits nestled within Silicon Valley, the premier high technology region of the world. Silicon Valley covers several cities in the south Bay Area region, and is home to many of the industry leaders in technology such as Google, Yahoo!, Cisco, Apple, Oracle, and Hewlett-Packard. Major corporations in San Francisco, San Jose, Oakland, and the surrounding cities help make the region second in the nation in concentration of Fortune 500 companies, after New York.