San Francisco is a major real-life city located in the US state of Cailfornia. In the first and second game of the SimCity series, San Fransisco is rocked by a massive earthquake as part of a scenario. This earthquake sparks massive fires that burn through the city until there is nothing left. In SimCity and SimCity 2000 they are based on real events. In SimCity 4 it is a region.
Official description: "San Francisco - In October of 1989, the Loma Prieta earthquake, centered in Santa Cruz, did extensive damage to San Francisco and neighbouring tons, including Oakland. Many fires broke out as a result of broken gas mains. Contain any fires, clean up the mess and rebuild the city population to 68,000 in five years to win this scenario."
In SimCity 4, San Francisco is instead a pre-made region based on a terrain map where the player can build on and develop buildings and life on. It features the San Francisco Bay Area, although it does not include the northern bay area.
The scale of the map is smaller than real life, so the player would not be able to reach the Bay Area's real life population, which is roughly 7,000,000 people. The City of San Francisco is also divided into 4 medium sized maps instead of all one large map.