Silicon Valley is the global center for high technology and innovation. It is located in Santa Clara County and southern San Mateo County within the Santa Clara Valley and the San Francisco Bay Area. Sunnyvale, Mountain View, Palo Alto and Menlo Park are frequently cited as the birthplace of Silicon Valley. Other major Silicon Valley cities are San Jose, Santa Clara, Redwood City and Cupertino.
It was in Silicon Valley that the silicon-based integrated circuit, the microprocessor, and the microcomputer, among other technologies, were developed. Today, Silicon Valley is home to many of the world's leading high-tech corporations, including the headquarters of more than 30 businesses in the Fortune 1000, and thousands of startup companies. The Bay Area also accounts for one-third of all of the venture capital investment in the United States, despite the tech ecosystem becoming more geographically dispersed. As of 2021, Santa Clara and San Mateo Counties employed about a half million information technology workers. Many headquarters of tech companies in Silicon Valley have become hotspots for tourism.
As of 2015, San Jose's metropolitan area, which comprises the bulk of Silicon Valley, had the third-highest GDP per capita in the world (after Zurich and Oslo), according to the Brookings Institution. As of June 2021, it also had the highest percentage of homes valued at $1 million or more in the United States, at 47%.
As more high-tech companies were established further north in San Francisco and the East Bay, the term "Silicon Valley" came to have a second metonymical definition referring to high-tech businesses in the entire Bay Area. The name also became a global synonym for leading high-tech research and enterprises, and thus inspired similarly named locations, as well as research parks and technology centers with comparable structures all around the world.




