LEWISTON – A Canadian financial group agreed Thursday to take control of Maine-based Banknorth for $3.8 billion, but the only difference local folks might notice from the merger is the disappearance of the name “Peoples.”

Canada’s TD Bank Financial Group is buying a 51 percent stake in Banknorth Group Inc., a deal that could fuel the Portland-based bank’s expansion into populous markets south of New England.

Banknorth will change its name to TDBanknorth by the end of the year, according to Michael McNamara, president of Peoples Heritage Bank. Following the parent company’s lead, People’s Heritage Banks will also adopt the TDBanknorth name, a switch that will end a 129-year-old association between local banking and the name Peoples.

“We know there are lots of roots here,” said McNamara. Peoples Savings Bank was founded in Lewiston in 1875.

But that should be the only change noticed locally. McNamara said there are no plans to close branches, lay off workers or make computer conversions. “Our employees are happy with the news; they’re grinning from ear to ear,” he said.

Banknorth employs 2,600 people in Maine, about 1,000 of whom are at the Peoples operations center in the Bates Mill.

McNamara said Banknorth gains an investment partner to continue its aggressive growth. The New England bank was the fourth-largest bank in Maine in terms of deposits 10 years ago; now it’s No. 1.

The company has been growing internally as well, buying banks in Massachusetts and Connecticut during the past several years, and expanding its financial products into insurance and investment industries.

The company now has more than 350 branches in New England and upstate New York, with assets of $29.3 billion. It has been viewed in recent years as a potential takeover target. TD Bank, based in Toronto and owner of Toronto-Dominion Bank, has assets of nearly $240 billion and more than 1,000 branches across Canada.

The cash and stock deal announced Thursday gives TD Bank a presence in the Northeast while allowing Banknorth to continue its growth strategy of acquiring small community banks.

“It really is a win-win situation,” said McNamara.

Banknorth shares, which gained 10 percent Wednesday on the New York Stock Exchange after news of ongoing discussions between the two groups, fell 98 cents Thursday to close at $33.90. TD Bank’s U.S. shares fell to $33.35, an 82-cent drop.

Ed Clark, TD Bank Financial Group’s president and chief executive, said the deal would give an immediate boost to his company’s earnings and provide “an outstanding personal and commercial banking complement to our strong U.S. wealth management franchise.”

The deal, which is subject to shareholder and regulatory approval, is expected to close in February, officials said.

“From our perspective, we are gaining access to capital and additional flexibility to allow us to continue to participate in larger acquisitions,” Banknorth Chief Executive Bill Ryan said. He said the deal should enable Banknorth’s assets to grow to between $40 billion and $60 billion, a level it would not reach on its own anytime soon.

On a conference call with analysts, Ryan suggested that the ability to tap TD’s capital would also expand the geographic reach of Banknorth’s acquisitions.

He said the New York metropolitan area, New Jersey and Pennsylvania would be “open territory” for a bank whose only foray outside New England has been in smaller upstate New York markets.

Asserting that TD had limited opportunities to redeploy its excess capital in Canada, Clark said he was looking for a well-managed and culturally compatible U.S. bank that could serve as a springboard for his company’s growth south of the border.