Silicon Valley includes the southern half of the San Francisco Peninsula and southern portions of the East Bay.
The region has expanded to include the southern half of the San Francisco Peninsula in San Mateo County , and southern portions of the East Bay in Alameda County .	San Francisco Peninsula	San Francisco Peninsula	San Mateo County	San Mateo County	East Bay	East Bay (San Francisco Bay Area)	Alameda County	Alameda County	San Francisco	San Francisco
