Pipeline company TransCanada said the $10.2 billion acquisition of a regional rival could make it the largest natural gas transmitter in North America.

TransCanada reached an agreement to acquire Columbia Pipeline Group, which has more than 15,000 miles of pipelines stretching from New York to the Gulf of Mexico. Columbia's holdings are positioned near some of the more lucrative shale natural gas basins in the United States.

"The acquisition represents a rare opportunity to invest in an extensive, competitively positioned, growing network of regulated natural gas pipeline and storage assets in the Marcellus and Utica shale gas regions," Russ Girling, TransCanada's president and chief executive officer, said in a statement.

TransCanada in recent years has focused on expanding oil pipeline networks in North America. The company is suing the federal U.S. government over the denial in 2015 of a permit to build the Keystone XL pipeline across the U.S.-Canadian border. Canadian Prime Minister Justin Trudeau, meanwhile, has expressed reservations about adding pipeline infrastructure in national territory.

The move into the gas network with the Columbia deal gives TransCanada control over roughly 1.3 trillion cubic feet of gas flows per year, including storage systems positioned in the United States.

The board of directors at Columbia unanimously approved the acquisition. CEO Robert Skaggs said that, with a 32 percent return on premiums, it's a deal that "delivers tremendous value to our shareholders."

Looking ahead, TransCanada said its $10.3 billion portfolio, combined with Columbia's $7.3 billion in projects, means it's starting a new chapter of operations.

"We are well positioned to generate significant growth in earnings into the next decade," Girling said.

The company in mid-2015 started a restructuring initiative aimed at making its existing operations more effective while leaving its general corporate strategy in place.