Apple, Google and Intel soon won't have to travel across the U.S. to get patent protection on their latest inventions.

Silicon Valley, Dallas and Denver have been selected as the new homes for regional patent offices as part of an effort to cut down on a backlog of applications awaiting review, the U.S. Patent and Trademark Office said Monday.

The agency, which is opening a satellite office July 13 in Detroit, and has declared a "critical need for electrical engineers," is trying to hire more examiners to cut into the 640,000 applications awaiting a first review.

By expanding beyond its campus outside Washington, D.C., the patent office seeks to take advantage of a pool of engineers who understand technology and can work closer to where inventors work.

"Silicon Valley was a logical location to us, but it was by no means a foregone conclusion it would be in California or in Silicon Valley," said Carl Guardino, president of the Silicon Valley Leadership Group, which lobbied for more than three years to get a patent office in Northern California.

Silicon Valley is the top recipient of patents, with more than 10,000 issued in 2010, agency figures show.

The additional offices were authorized under an overhaul of the patent system signed into law last year. About 600 applications were submitted, and the selections were based on geographic diversity, economic impact, the local workforce and proximity to companies that are submitting applications.

"The single most important step we can take to support an economy built to last is to bring new inventions to market as quickly as possible," said David Kappos, director of the Patent and Trademark Office.

The regional offices would become hubs with "a tangible impact on each city's innovation economy," Kappos said. He said the office could bring in law firms, entrepreneurs and investors as a sort of ecosystem to interact with the agency.

The four offices also could develop their own expertise to reflect local communities — Detroit for automotive, metallurgy and paints; Dallas for energy; Denver for aerospace; and Silicon Valley for electronics and biotechnology.

Denver also was selected in part because it has a large number of veterans with advanced degrees, and President Obama's administration has a policy to hire more veterans, Kappos said.

Denver said it beat out competition from Portland; Seattle; Salt Lake City; and Albuquerque, N.M., because of its educated workforce, relatively low cost of living and research in bioscience, aerospace and renewable energy.

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