Silicon Valley is a nickname for the southern portion of the San Francisco Bay Area, which is located in the part of the U.S. state of California known as Northern California. It is home to many of the world's largest high-tech corporations and thousands of startup companies. Geographically, it encompasses all of the Santa Clara Valley, the southern half of the San Francisco Peninsula, and southern portions of the East Bay. It includes parts or most of Santa Clara County, San Mateo County, and Alameda County. San Jose is considered to be the "capital" of Silicon Valley.
The word "valley" refers to the Santa Clara Valley, where the region has traditionally been centered, which includes the city of San Jose and surrounding cities and towns. The word "silicon" originally referred to the large number of silicon chip innovators and manufacturers in the region. The term "Silicon Valley" eventually came to refer to all high tech businesses in the area, and is now generally used as a synecdoche for the American high-technology economic sector. It also became a global synonym for leading high-tech research and enterprises, and thus inspired similar named locations, as well as research parks and technology centers with a comparable structure all around the world.
Silicon Valley is a leading hub and startup ecosystem for high-tech innovation and development, accounting for one-third of all of the venture capital investment in the United States. It was in the Valley that the silicon-based integrated circuit, the microprocessor, and the microcomputer, among other key technologies, were developed. As of 2013, the region employed about a quarter of a million information technology workers.
"Perhaps the strongest thread that runs through the Valley's past and present is the drive to 'play' with novel technology, which, when bolstered by an advanced engineering degree and channeled by astute management, has done much to create the industrial powerhouse we see in the Valley today." (Timothy J. Sturgeon)