San Francisco, officially known as the City and County of San Francisco, is a major city located in California. It ranks as the fourth-most populous city in the state and the 17th-most populous city in the United States, with a population of 826,079 as of 2025.
The city is characterized by high economic metrics; it ranks first in per capita income among U.S. cities with populations over 200,000 and sixth in aggregate income as of 2024. It also holds the third-highest population density among cities of similar size. The surrounding metropolitan statistical area houses approximately 4.6 million residents, while the larger San Jose–San Francisco–Oakland combined statistical area contains roughly 9.2 million people.