TRUCKEE — A breathtaking landscape of Sierra Nevada meadows, forests and wetlands larger than San Francisco’s Golden Gate Park — located 20 miles north of Lake Tahoe — will be preserved from development under a $10 million deal that closed Friday.

The Lower Carpenter Valley area that was purchased is 1,317 acres, a hidden valley one ridge over from the Tahoe Donner ski resort that is home to bald eagles, black bears, carpets of wildflowers and an unspoiled stream — all flanked by snow-capped peaks.

A coalition of conservation groups known as the Northern Sierra Partnership, which is based in Palo Alto and funded in large part by donors from Silicon Valley and the rest of the Bay Area, feared that the land would be developed as a golf course or housing subdivision. So the groups stepped in to acquire the property when it was about to hit the market.

“We are in a race with developers,” said Lucy Blake, president of the Northern Sierra Partnership. “People are building second homes up here. It’s tied to the prosperity of the Bay Area. We are trying to protect and connect the large landscapes of the Northern Sierra.”

The partnership was founded in 2007, largely by Jim Morgan, the retired CEO and chairman of Applied Materials, a Santa Clara-based company that builds the equipment to make semiconductor chips, and his wife, Becky Morgan, a former Republican state senator. The partnership includes the Nature Conservancy, the Sierra Business Council, the Feather River Land Trust, Truckee Donner Land Trust and Trust for Public Land.

The group’s original goal a decade ago was to raise $100 million in private money and preserve 100,000 acres between Lake Tahoe and Mount Lassen. So far, the partnership has raised roughly $60 million and preserved 69,371 acres.

Its main tactic is to purchase land or development rights from willing sellers. Much of the property is adjacent to national forests and exists in checkerboard patterns of private and public land that originated when President Abraham Lincoln’s administration gave every other square mile of land within 20 miles on either side of Donner Summit to railroads in the 1860s to encourage development of the Transcontinental Railroad.

The group has preserved areas from Independence Lake north of Truckee to meadows in Martis Valley on Lake Tahoe’s northern edges, to the rocky crags of Castle Peak, Sierra Valley and the Royal Gorge area west of Lake Tahoe.

When it began, land was cheap as the Great Recession raged. Developers had little demand and timber companies in the area weren’t selling much lumber because the market to build new housing had collapsed.

But today the economic rebound is putting renewed development pressure on the area. Although 90 percent of the land in the central and southern Sierra Nevada is preserved in national parks like Yosemite or Sequoia-Kings Canyon, wilderness areas or national forests, only 50 percent of the Northern Sierra is preserved.

In recent years, golf courses have sprung up, along with luxury subdivisions and other developments. The Truckee Airport buzzes with private jets, and ski resorts in the area are looking to expand.

In November, Squaw Valley, which hosted the 1960 Winter Olympics, won approval from the Placer County Board of Supervisors for a $1 billion expansion with 850 new hotel, condominium and residential units, along with new shops, bowling alleys, movie theaters, restaurants and an indoor water park. Environmental groups have since sued to scale back that project. And developers are lining up with other projects.

“It’s back to the good old days,” said Perry Norris, executive director of the Truckee Donner Land Trust. “Real estate agents here are seeing multiple offers at full asking price. In some ways, protecting this property is drawing an urban growth boundary.”

Hiking through Lower Carpenter Valley earlier this week, through knee-deep green grass and carpets of red Indian Paintbrush and purple lupin flowers, Norris noted that just over the ridge tops are 5,000 homes at the Tahoe Donner ski area. Carpenter Valley would have been coveted by developers, he said.

“You’d have McMansions and tennis courts in the middle of the meadow,” he said. “Instead, in 50 or 100 years it’s going to look pretty damn close to the way it is now.”

The Northern Sierra Partnership, along with the Nature Conservancy and Truckee Donner Land Trust, led the efforts to purchase the property for $8 million. Another $910,000 was raised to build trails, a foot bridge, a caretaker cabin and split-rail fencing, and $1.34 million was raised to fund permanent stewardship of the valley, which will be open to the public for hiking and cross-country skiing in several years.

The previous owners were three friends who used it as a rural getaway and fishing area. They were James McClatchy, the former chairman of the McClatchy Company, which owns the Sacramento Bee and 29 other newspapers; Dr. Richard Cobden, a surgeon from Fairbanks, Alaska; and Charles Willis, CEO of Willis Lease, a Novato company that leases aircraft engines to commercial airlines.

McClatchy, a Stanford University graduate who learned of the property from a former classmate in the 1980s, served on the board of the California Nature Conservancy. He died in 2006 at age 85.

“He was of the feeling that private citizens should help with conservation,” said his widow, Susan McClatchy, of Carmichael.

James McClatchy, who owned the Sierra Sun and Tahoe World newspapers and who had a home at Lake Tahoe, was concerned about preserving the most important areas of the Sierra for wildlife and for water, since large amounts of California and Nevada’s water supply come from the Sierra Nevada’s snowpack and streams each year, his widow said.

“My husband used to say that this is what Squaw Valley looked like 100 years ago,” she said of Lower Carpenter Valley. “We would go over for days and have a wonderful time. He just wanted to preserve it.”

As part of the deal, roughly half of the property was sold to Tahoe Donner ski resort, but with legally binding conservation easements that allow no development, only hiking, cross country skiing and other low-impact recreational uses. The rest will remain a preserve owned by the Truckee Donner Land Trust.

“It’s the most exquisite piece of the puzzle,” Blake said. “You get one chance to preserve a place like this. It doesn’t come around again.”