MARLBOROUGH – Amazon’s second headquarters will not be coming to MetroWest, but local officials still hope the region will financially benefit if Boston is picked for HQ2.

The company announced Thursday it had chosen 20 cities – including Boston – out of 238 proposals that will advance to the next step of finding a home to complement its existing base in Seattle. Amazon is promising $5 billion of investment and 50,000 jobs in whichever North American region it selects.

"I am proud that Boston is on Amazon's shortlist for its second North American headquarters," Boston Mayor Marty Walsh said in a statement. "As a thriving city with a talented and diverse workforce, culture of innovation and opportunity for all, I see no better city than Boston for Amazon to call their second home."

One of those left off Amazon’s list was a regional proposal spearheaded by the Marlborough Economic Development Corp. The five-community partnership called the 495 Crossroads Task Force called for the creation of a north campus in Marlborough and Northborough and a south campus in Southborough and Westborough across 10 different properties Amazon could build or lease. Hudson was also involved, but no properties were listed.

The 10 sites include 6,614,812 square feet of office or build-out space.

The group’s application touted MetroWest as being the heart of the state’s innovation ecosystem.

Mayor Arthur Vigeant remains optimistic Amazon could still locate smaller manufacturing facilities in Marlborough or MetroWest if Boston is chosen to house the online giant’s second headquarters, dubbed HQ2.

“We said from the beginning we want to get some of the residual business,” said Vigeant.

In an email to the task force, Amazon said it plans to keep the proposal on hand for the future.

Paul Matthews, executive director of the 495/MetroWest Partnership, also believes MetroWest could benefit from Boston earning the bid through potential secondary investments made by Amazon. The company coming to Boston would be advantageous for the region’s vast number of skilled workers.

A disappointed Matthews said he is not tremendously surprised the regional bid did not make the cut.

“This is really the holy grail of economic development,” he said. “These opportunities don’t come along every day, every week, every year.”

Matthews called the five communities’ efforts to lure Amazon a huge win for the region.

Meredith Harris, executive director of the Marlborough Economic Development Corporation, said the proposal provides a framework that can be used to attract other companies in the future.

“It sets us up for that,” said Harris. “It was well-worth the investment.”

The company will work with the 20 finalists in the coming months for a more extensive review of the proposals and evaluate how those areas could accommodate Amazon’s hiring plans. Amazon expects to make a decision on the site this year.

Material from State House News Service was used in this report.

Jeff Malachowski can be reached at 508-490-7466 or jmalachowski@wickedlocal.com. Follow him on Twitter @JmalachowskiMW.