Silicon Valley

The term Silicon Valley was invented in the mid 1970s. Naturally, the local residents had names for their region prior to this newfangled name, such as "Santa Clara Valley" and "Valley of Heart's Delight," and still use them. The term Silicon Valley overlaps several of the pre-existing names for this region including parts of the South Bay and Peninsula. While there are hi-tech companies all along the west coast — from Canada down to Mexico — and many in various parts of California, the main cluster is in Silicon Valley.
Because the electronics industry is considered somewhat prestigious, nearby communities often redefine the term Silicon Valley to include themselves. Some of these communities were mostly farmland when the term was invented, so it was pretty natural that the term didn't originally include them, but they might reasonably be considered part of the Silicon Valley now. On the other hand, the Mercury News's Silicon Valley 100 Index extends the term to such fabulous lengths that even Watsonville — a small coastal community on the other side of the Santa Cruz mountains — is included.
So if you're looking to visit the Silicon Valley as a tourist, look to Palo Alto, Santa Clara, and the museums of San Jose. But if you're visiting a company which is "in the Silicon Valley," you may have to look further afield around the South Bay, Peninsula, and East Bay regions.

Birthplace of Silicon Valley

Designated by the State of California as a historical landmark, the "HP Garage" located at 367 Addison Avenue, Palo Alto, is the birthplace of the world's first high-technology region, "Silicon Valley."
As inscribed on the monument, "the idea for such a region originated with Dr. Frederick Terman, a Stanford University professor who encouraged his students to start up their own electronics companies in the area instead of joining established firms in the East. The first two students to follow his advice were William R. Hewlett and David Packard, who in 1938 began developing their first product, an audio oscillator, in this garage."
The HP Garage was designated California Historical Landmark No. 976 in 1989.

Stanford Research Park

In the 1950s, Professor Frederick Terman suggested to Stanford University that the newly founded Stanford Industrial Park leases be limited to high-tech companies so a center of high technology could be created.
In October 1951, Varian Associates signed a lease with the university for a 10-acre tract along El Camino Real and built their $1 million R&D laboratory in the Stanford Industrial Park the following year. Soon after, Eastman Kodak, General Electric, Preformed Line Products, Admiral Corporation, Beckman Instruments, Lockheed, Hewlett-Packard, and others followed suit.
Stanford Industrial Park was renamed Stanford Research Park in 1974.
By 2005, Stanford Research Park was home to more than 150 companies in electronics, software, biotechnology, as well as a number of top law firms, financial service firms, consultancies, and venture capital companies. R&D and service companies occupied some 10 million square feet in more than 160 buildings on 704 acres.
Stanford Research Park is considered by many the foundation of Silicon Valley.

Shockley and Fairchild

William Shockley was a Bell Labs physicist and one of a group there who got a Nobel Prize for inventing the transistor. In 1956 he opened his own electronics company in Mountain View, the area he had grown up in. Only a year later, some of his young engineers (the "traitorous eight") left to found Fairchild Semiconductor in San Jose. Fairchild was the first company to use silicon rather than germanium for its transistors and the first to succeed in producing integrated circuits commercially. Like the other major players of the era — Texas Instruments and Motorola — Fairchild Semiconductor was a branch of a large firm well established in other areas of electronics.
Many of Silicon Valley's best-known companies were started by "the Fairchildren", people who learned their trade at Fairchild then left to try their own ventures. By one estimate, there are about 400 such companies. Unlike the earlier semiconductor firms, these were independent startups without ties to existing companies; this started a trend which continues to this day. Two of the "traitorous eight" who founded Fairchild Semi later started Intel in Sunnyvale. Other "Fairchildren" companies include AMD (in Sunnyvale), National Semiconductor (Santa Clara) and Intersil (Milpitas).

Origin of the Name

"Silicon Valley", first used by Don C. Hoefler, publisher of Microelectronics News, in his article titled "Silicon Valley USA" on January 11, 1971, has become synonymous with the center of high technology research and development. "Silicon" refers to the high concentration of semiconductor and computer-related industries in the area at the time. "Valley" refers to the Santa Clara Valley.
Silicon Valley today has extended beyond the greater Santa Clara Valley which includes the entire Santa Clara county and parts of San Mateo, Alameda, and Santa Cruz counties in northern California. It is the southern portion of the San Francisco Bay Area, also known as, South Bay, which covers cities such as San Jose, Santa Clara, Sunnyvale, Cupertino and Los Gatos. Silicon Valley also includes parts of the San Francisco Peninsula from Redwood Shores down to the South Bay, and cities such as Fremont and Newark in the lower East Bay.

San Jose Airport is connected to the local light rail by a free shuttle bus, or you can get one of the scheduled bus services that service the airport as well . Taxis also serve the airport and can transport you to Sunnyvale for around $25 one way, for example.
San Jose Airport connects to Caltrain by VTA bus line 10, a free shuttle between the airport and the Santa Clara Caltrain station and transit center. Various other local VTA bus lines also leave from this transit center.
From the San Francisco International Airport (SFO) use the BART connection to Caltrain and take Caltrain south. Note that the two train systems require separate tickets.

Its quite possible to see Santa Clara and San Jose by public transport and walking. Outside of those cities, the best way to travel in Silicon Valley is car due to weak public transportation infrastructure (though not during rush hours).

People sometimes visit company headquarters in Sillicon Valley so they can take a photo at them.
Major points of interest include the Tech Museum of Innovation in San Jose and the Computer History Museum in Mountain View, as well as Stanford University's campus just south of Palo Alto.

Fry's Electronics began in Sunnyvale in the 80s; they originally sold mainly parts for do-it-yourself hardware hackers. Since then they have grown considerably; they are now much more of a general-purpose electronics vendor have over 30 locations, mostly in various western US states plus a few further east. The original store, however, is a bit of a pilgrimage site for hackers and still a good place for otherwise hard-to-find items.
Google, Apple and Intel have company stores at their respective headquarters selling branded merchandise such as apparel, mugs, and various gifts. It is worthy to note that the two such Apple "gift shops" in Cupertino have exclusive products, sometimes in limited edition, that cannot be purchased anywhere else and are different in both shops.