ADIRONDACKS — One hundred and fifty years after a Schenectady painter organized one of the Adirondacks’ most legendary camping trips along the shore of Follensby Pond, a preservation group has bought the lake with the intention of adding it to the state’s public lands.

The Nature Conservancy announced Thursday its $16 million purchase of Follensby Pond near Tupper Lake in the central Adirondacks. The deal for the 14,600-acre forest tract brings to conclusion a nearly three-decade-long conservation effort initially spearheaded by two Schenectady County residents. The property famously housed Ralph Waldo Emerson’s “Philosophers’ Camp.”

Manchester Depot, Vt., resident John McCormick Jr. agreed to sell the pristine tract, which he bought in 1952. Follensby had been the largest single-party owned body of water in the Northeast.

The deal came 14 years after the state unsuccessfully tried to buy the tract, which borders the High Peaks Wilderness Area. That failed 1994 bid sidelined the preservation efforts of David Newhouse of Schenectady, the former president of the Adirondack Mountain Club, and Paul Schaefer of Niskayuna, the former president of the Association for the Protection of the Adirondacks.

“We know that many people are eager to visit Follensby Pond but ask that the public be patient as we work through the transactional and transitional details,” Michael Carr, executive director of The Nature Conservancy’s Adirondack Chapter, said in a statement.

Follensby will remain off limits until the state is able to buy the land and add it to the Adirondack Forest Preserve, a process Adirondack Mountain Club Executive Director Neil Woodworth said could take up to five years. But even after that, the nearly 5-mile-long lake will likely be accessible only via canoe or kayak.

“You’re not going to be able to drive up to the Philosophers’ Camp,” Woodworth said.

During the summer of 1858, Schenectady native William James Stillman led a group of nine New England intellectuals into the Adirondack wilderness. The group of 10 “luminaries” established what they dubbed “Camp Maple” near the Follensby’s southern shore.

Emerson canonized the adventure in his 1867 poem “The Adirondacs.” Stillman’s “Camp Maple” painting is the most popular art work hanging in the Concord Free Public Library in Concord, Mass.

The pending land sale and 150th anniversary of the Philosophers’ Camp was the subject of a June 22 Sunday Gazette feature package, which provided a rare glimpse of Follensby. Saranac Lake historian Alfred Donaldson called the 1858 gathering “the most illustrious and variegated group of intellectuals who ever camped out in the Adirondacks.”

Stillman, who was born in Schenectady in 1828 and graduated from Union College in 1848, organized the Philosophers’ Camp at a time when the Adirondacks were still largely known only to wealthy hunters and landscape painters. The group included Emerson, poet Robert Lowell, Swiss-American scientist Louis Agassiz and Ebenezer Hoar, who later served as attorney general under President Ulysses Grant.

The Adirondack tourism industry took off after the Civil War and Follensby became a popular tourist destination. But by the 1880s, tourists had decimated its once-virgin forest. While Follensby’s woodlands have recovered, flush with cedars, hemlocks and maples, McCormick strictly restricted access to the lake for more than a half century.

Starting around 1980, the Adirondack Mountain Club, under Newhouse’s leadership, began lobbying for the state’s acquisition of Follensby. By 1990, Schaefer at the Association for the Protection of the Adirondacks also started rallying for the preservation of Follensby. The tract was listed in 1992 on the first New York State Open Space Conservation Plan, and it has landed on that high-priority property acquisition list since then.

In a November 1992 letter, McCormick assured Schaefer, “You can rest assured that Follensby Park will not be sold to a developer. It belongs to the Park, and I hope someday it will be.” He also called the Niskayuna man “almost the living symbol of the Adirondacks.” But McCormick two years later backed out of a deal to sell the land, mostly because of state funding difficulties.

McCormick, who is now is his mid-90s, again opened up to the notion of selling Follensby after the January 2007 death of his wife, Bertha “Bird” McCormick, a former chairwoman of Vermont’s Nature Conservancy chapter. McCormick and his family vacationed frequently at Follensby and the family lodge there called White Birches. In August 2007, he auctioned many of White Birches’ historic items.

“My wife was a true conservationist, and together, we’ve long envisioned Follensby one day becoming part of the publicly owned forest preserve. I have every confidence that the Nature Conservancy and New York state will work together over the next few years to make that happen,” McCormick said in a statement.

Two of Follensby’s biggest preservation supporters will not be able to paddle along Follensby. Schaefer died in 1996 and Newhouse in 2006. But Association for the Protection of the Adirondacks Executive Director David Gibson said Schaefer held on to McCormick’s 1992 letter and trusted Follensby would eventually be open to the public.

“He knew how important [Follensby] was. It was an important piece of the puzzle,” Gibson said.