The San Jose-San Francisco-Oakland Bay Area, commonly referred to as the Bay Area, is a populated region that surrounds the San Francisco and San Pablo estuaries in Northern California. The region also surrounds a number of other bays including San Leandro Bay, Suisun Bay, San Rafael Bay, Richardson Bay, Grizzly Bay, and Honker Bay. The region encompasses the major cities and metropolitan areas of San Jose, San Francisco, and Oakland, along with smaller urban and rural areas. The Bay Area's nine counties are Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano, and Sonoma. Home to approximately 7.44 million people, the nine-county Bay Area contains many cities, towns, airports, and associated regional, state, and national parks, connected by a network of roads, highways, railroads, bridges, tunnels and commuter rail.