Silicon Valley is still the epicenter of the tech startup world, but there's a long list of cities looking for a piece of the entrepreneurial pie.

Not surprisingly, San Francisco and San Jose, Calif. — both within the Silicon Valley region — are the top two cities, respectively, for venture capitalist investments in tech startups, according to National Venture Capital Association (NVCA), based on data from Thomson Reuters and the MoneyTree Report by PwC. The rankings were first posted to CIO.com.

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But right up against those likely contenders is New York City at No. 3, which has become an increasingly popular stomping ground for budding businesses — thanks in part to companies such as Google and Facebook setting up offices in the city, as well.

Rounding out the top Boston at No. 4 and Los Angeles at No. 5.

"Venture capitalists will go to where the entrepreneurs are — and there is a great deal of startup activity outside of Silicon Valley," a NVCA spokesperson told Mashable. "Those regions with thriving VC ecosystems tend to have strong universities where technology is developed and research is completed and commercialized."

"There is also a supportive community of service providers able to help startups get off the ground," the spokesperson added. "Once a foundation is formed, it feeds upon itself and grows organically."

For a full look at the top cities — and some may surprise you (Pittsburgh?) — check out the list below:

1. San Francisco 2. San Jose, Calif. 3. New York City 4. Boston 5. Los Angeles 6. Washington D.C. 7. Seattle 8. Austin 9. Philadelphia 10. Chicago 11. Oakland, Calif. 12. Atlanta 13. Pittsburgh 14. Denver, Colo. 15. Boulder, Colo.

What other cities are making a big impact on the tech startup scene? Let us know in the comments below.

Image via Flickr, JoisyShowaa