San Francisco Metropolitan Area officially known as the San Francisco-Oakland-Hayward, CA Metropolitan Statistical Area is a Metropolitan Statistical Area (MSA) within the San Francisco Bay Area, which includes a number of its core cities and counties. It is the eleventh-most populated metropolitan area in the United States. It is defined by the Office of Management and Budget to include core areas more directly economically influenced by San Francisco rather than other nearby cities such as San Jose which has its own MSA, the San Jose–Sunnyvale–Santa Clara, CA MSA. Until 2013, this MSA was known as the San Francisco–Oakland–Fremont, CA MSA.
The Federal Government definition states that it consists of 5 counties, grouped into three divisions. Those 5 counties are San Francisco, Alameda, Marin, Contra Costa, and San Mateo County. The three divisions are Oakland–Hayward–Berkeley (Alameda and Contra Costa Counties), San Francisco–Redwood City–South San Francisco (San Francisco and San Mateo Counties), and San Rafael (Marin County).
The MSA is a subset of the 9 county San Francisco Bay Area, as well as the 12 county Combined Statistical Area, the San Jose–San Francisco–Oakland, CA CSA. Three North Bay counties are not in the MSA; instead Sonoma County comprises the Santa Rosa, CA MSA, Napa County comprises the Napa, CA MSA, and Solano County is the Vallejo–Fairfield, CA MSA.
|State Census data 
This region had a 2017 census-estimated population of 4,727,357. With a land area of 2,474 square miles (6,410 km2), the MSA has an average population density of 1,911 people per square mile (738 per km2).
The U.S. Census Bureau estimates the population of this five-county region as of July 1, 2017 as follows:
|County||2017 Estimates||2010 Census||Change||Area||Density|
|Alameda County||1,663,190||1,510,271||+10.13%||738 sq mi (1,910 km2)||2,254/sq mi (870/km2)|
|Contra Costa County||1,147,439||1,049,025||+9.38%||720 sq mi (1,900 km2)||1,594/sq mi (615/km2)|
|San Francisco||884,363||805,235||+9.83%||47 sq mi (120 km2)||18,816/sq mi (7,265/km2)|
|San Mateo County||771,410||718,451||+7.37%||449 sq mi (1,160 km2)||1,718/sq mi (663/km2)|
|Marin County||260,955||252,409||+3.39%||520 sq mi (1,300 km2)||502/sq mi (194/km2)|
|Total||4,727,357||4,335,391||+9.04%||2,474 sq mi (6,410 km2)||1,911/sq mi (738/km2)|
The GDP of the region was $431.7 billion (nominal) in 2015, a 5.8% annual increase. The region is the 7th largest MSA economy.
There is a vast geographic diversity within this MSA. The region is composed of at least six terrains (continental, seabed, or island arc fragments with distinct characteristics) pushed together over millions of years by the forces of plate tectonics. There are several fault lines running under the Bay Area, such as the San Andreas, Calaveras, and Hayward Faults. There are two distinct regions of the San Francisco–Oakland–Hayward, CA MSA which are separated by the San Francisco Bay. These landscapes range from cool foggy mountains and temperate rainforest on the Peninsula and Marin, to semi-arid, near desert terrain in the easternmost portions of the East Bay.
Bay Area Rapid Transit serves all the counties except Marin. Golden Gate Transit serves Marin, with limited connections to San Francisco and Contra Costa, along with service to outlying Sonoma County. AC Transit serves Alameda and Contra Costa, with connections to San Francisco's transit hub. Commercial air travel is available via San Francisco International Airport, and Oakland International Airport.
In addition to the city and county governments, there are a number of area-wide governmental bodies. Park organizations in the area include the East Bay Regional Parks District and the Golden Gate National Recreation Area. East Bay Municipal Utility District provides water and sewer services to much of the East Bay, with the Marin Municipal Water District providing for parts of Marin County. The Association of Bay Area Governments provides for regional planning. The Bay Area Metropolitan Transportation Commission coordinates transportation projects. The Bay Area Air Quality Management District monitors air quality.