Key Bank closed its Gardiner branch Friday, sending customers who bank there to its Whitten Road location in Augusta.

The bank is selling the 139-year-old building, which has operated at the corner of Brunswick Avenue and Water Street as a financial institution for nearly a century.

Key Bank, headquartered in Cleveland, Ohio, closed the branch primarily because of decreased foot traffic, said Therese Myers, a spokeswoman for the bank. The ATM in the Gardiner Hannaford parking lot will remain open, she said.

Mobile banking is becoming more popular, and roughly 70 percent of the bank’s customer transactions are now done electronically, Myers said.

“People are just not going into branches across the country,” she said. “We’re seeing this everywhere.”

It’s the fifth Maine branch the bank has closed without a replacement since September, leaving the bank with 53 branches in the state, Myers said. Across the country, KeyBank closed 62 branches in 2013 and slated 31 for closing in 2014, she said.

The president of the Portland-based Maine Bankers Association, Christopher Pinkham, said there’s a growing popularity in electronic forms of banking, but no institutions are significantly abandoning branches overall.

“I think what you’re going to have is banks will have to evaluate how busy every branch is and how many transitions shift away,” Pinkham said.

Branches are also useful for marketing purposes because people will see a bank’s sign when they drive by a branch, he said. And while some transactions over the last two decades have shifted to telephone banking, online banking and now mobile banking, physical locations are still popular, especially for older customers, Pinkham said.

The total number of bank branches in Maine remained fairly consistent in the decade between 2003 and 2013. The total increased slightly in that time, rising from 507 to 515 and peaking at 520 in 2009, according to the Federal Deposit Insurance Corporation.

The Key Bank building in Gardiner has been a bank since 1927 when the Gardiner Trust Company opened its doors. It later became Depositors Trust Company, which was renamed Key Bank in 1984.

Before that, the building had a variety of uses including a hotel, a furniture store and, originally, a grocery store, according historical records provided by Dawn Thistle, the Gardiner Public Library’s special collections librarian.

Nate Rudy, the economic and community development director of the city, said he showed the building as part of tours of available properties in the city to a couple of prospective business owners, but he doesn’t know of any plans to buy the building.

The seller for the agency listing the property, Magnusson Balfour Commercial & Business Brokers in Portland, didn’t respond to a phone call for comment. The company is listing the property for $189,500 on its website.

“Certainly it’s a high-profile building in a very good location,” Rudy said, “and we’re very eager to see who our new neighbor is going to be.”

Paul Koenig — 621-5663 | [email protected] | Twitter: @paul_koenig