Mary Gertrude Anderson

Mary Anderson, who, with her husband, founded the mountaineering importer in 1938 that became REI and helped it grow into the nation’s largest consumer cooperative without betraying its founding principles, died on March 27 in the Puget Sound region of Washington State. She was 107.

An REI spokesman confirmed her death.

Avid climbers and outdoor enthusiasts, Mrs. Anderson and her husband, Lloyd, were unhappy with the ice axes available in the United States in the 1930s. So they began to import less expensive, high-quality ice axes from Austria, and these soon caught the eyes of their climber friends.

In 1938, 21 of those friends paid $1 each for a lifetime membership in the Andersons’ company, originally the Recreational Equipment Cooperative, which imported outdoor equipment for lower prices than it could be bought domestically.

The idea behind the cooperative, a business model that peaked in the Depression, was to supply gear at fair prices and return some of the profit to members, in that way encouraging outdoor activities.

By the end of the year, membership had more than quadrupled, with members receiving a dividend based on the amount of gear they had bought. Over the following decades the Andersons ran REI from their Seattle home, where they stored most of their merchandise.

Mrs. Anderson made sure the operation ran smoothly by coordinating orders and deliveries, stitching tents and packaging food for expeditions. By the 1960s REI had outgrown the home.

The company continued to expand, and now offers equipment for outdoor activities like cycling, skiing, camping and hiking from a thriving catalog and online business and more than 140 stores in the United States.

In 2016, REI reported revenues of $2.56 billion and said that more than six million active members had received dividends or credit card rebates worth a high of $193.7 million. The company said it returns 70 percent of its profits to the outdoor community, including $9.3 million to nonprofit groups.

“I never thought a man should make money off his friends,” Mr. Anderson once told Timothy Egan, who wrote about REI last week in an Op-Ed column in The New York Times.

Mrs. Anderson retired in 1968, followed by Mr. Anderson in 1970, but their influence was still felt at REI.

Sally Jewell, a former REI chief executive and an interior secretary under President Barack Obama, said in an interview on Monday that Mrs. Anderson had helped create REI’s mail-order business, and that when she gave a speech to a large REI gathering in the mid-2000s, “it was like Mick Jagger” had appeared.

“I would say the women were particularly moved by the role she played and the fact that she was still around and proud to be associated with us,” Ms. Jewell said.

Mrs. Anderson was born Mary Gaiser in the Yakima Valley region of Washington on Dec. 7, 1909. She was a schoolteacher before REI became successful, and she often took her students on hikes and excursions.

Mr. Anderson died in 2000. Mrs. Anderson’s survivors include a daughter, Sue Anderson, and two grandsons. Another daughter, Ruth, died before her.

Shortly after Mrs. Anderson’s 100th birthday in 2009, the REI Foundation, a nonprofit organization supported by the company, announced a grant in her name to encourage young people to engage with nature and outdoor exploration.