Silicon Valley is in California. Located in San Francisco, it is called Silicon Valley because "silicon" has to do with the high concentration of businesses that manufacture semiconductors. The "valley" refers to the Santa Clara Valley, which is located at the southern end of San Francisco bay. It has been called Silicon Valley for 41 years. A company in the Silicon Valley made the World's first microprocessor named the Intel 4004 in 1971. Silicon valley is known for innovation in software and Internet.
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