Boulder, San Jose, and... Ann Arbor? These are America's top 12 tech hubs, according to Bloomberg

• Silicon Valley has long dominated the market for tech talent in the United States.
• But according to Bloomberg's 2019 Brain Concentration Index, there are plenty of smaller cities across the country giving the tech hub a run for its money.
• Cities on the index are ranked out 100 based on factors, such as what percentage of their populations work in science, technology, engineer or math jobs.
• Here are the top 12 tech hubs in the US, according to Bloomberg.
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Silicon Valley might have some competition for tech talent from... Ann Arbor, Michigan?

The Bay Area and its surrounding cities have long served as a tech hub that companies like Apple, Facebook, and Google parent Alphabet call home. But according to a new report from Bloomberg, there are smaller cities all over the country creating robust ecosystems of tech talent for companies to capitalize on.

Bloomberg released its 2019 Brain Concentration Index on Monday, a report that shows which cities have a high density of science, technology, engineering, and math professionals.

Each city is scored out of 100 based on three criteria: how many people have jobs in STEM, science and engineering degrees, and advanced degrees.

All three metrics are expressed as a percentage of the population of the city. The data goes up to 2018 and was pulled from the US Census report.

Many of the top cities on the lists are known as college towns or have a high concentration of universities in the surrounding area. And, of course, San Francisco makes an appearance.

Here are the top 12 tech hubs across America, according to Bloomberg's 2019 Brain Concentration Index. The list is ranked in increasing order of each city's score out of 100.