Silicon Valley is in California.
San Jose ( [ ˌsæn_hoʊˈzeɪ ] , Spanish for `` Saint Joseph '' ; [ saŋ xoˈse ] ) , officially the City of San José , is the economic , cultural , and political center of Silicon Valley and the largest city in Northern California . Santa Clara County , California , officially the County of Santa Clara , is a county in the U.S. state of California . Silicon Valley . The `` valley '' in its name refers to the Santa Clara Valley in Santa Clara County , which includes the city of San Jose and surrounding cities and towns , where the region has been traditionally centered .