Silicon Valley gets all the glory, but the real hotbed of American entrepreneurship appears to be a few hundred miles to the northeast: Montana.

The state leads the nation in business creation, according to a new report from the Kauffman Foundation, which produces an annual analysis and ranking of start-up activity in every state. This year, the organization expanded its study to include the 40 largest metro areas. Austin, Tex., took the top spot in that ranking, followed by Miami. San Jose, Calif., a tech industry center, came in third.

Kauffman’s data shows a heavy concentration of new business creation in the northern Mountain and Midwestern states. Why? Researchers point to the oil boom. The three states at the top of this year’s ranking — Montana, Wyoming and North Dakota — all touch the Bakken region, where a drilling frenzy brought a rush of development and thousands of new workers to once-sleepy towns, spawning entire industries. Oil- and gas-related start-ups are piling into the region, but so are restaurants, day care centers, breweries, equipment makers, clothing retailers, transportation businesses and an array of other ventures.

To create its ranking, Kauffman combines several economic measures, including the number of adults in an area who start businesses each month. In Montana, that rate is 540 for every 100,000 residents, nearly twice the national average.