Silicon Valley is a region in Northern California that serves as a global center for high technology and innovation. Located in the southern part of the San Francisco Bay Area, it corresponds roughly to the geographical areas San Mateo County and Santa Clara County. San Jose is Silicon Valley's largest city, the third-largest in California, and the tenth-largest in the United States. The San Jose Metropolitan Area has the third-highest GDP per capita in the world (after Zurich, Switzerland and Oslo, Norway), according to the Brookings Institution, and, as of June 2021, has the highest percentage of homes valued at $1 million or more in the United States.