This coveted Bay Area mountaintop will open to the public for the first time in decades
A privately owned mountaintop in the heart of Marin County off-limits to the public for decades will soon be set aside as open space, offering hikers a new summit to explore.
On Tuesday, the Marin County Board of Supervisors is expected to approve transfer of a 161-acre property atop King Mountain, an oak- and redwood-studded knoll a few blocks from downtown Larkspur that the county calls "an iconic natural landscape," to county ownership. With funding from a charitable foundation, the property was recently purchased by Marin Open Space Trust for permanent protection, marking a victory for conservationists who have long considered it to be a missing piece of a prime hiking preserve.
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"This is one of the last ridgetops in Marin that had yet to be protected," said Chris Chamberlain, Marin County Parks director. "It's an exciting moment for the community and for us."
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The undeveloped knob of land rests just below the eastern peak of Mount Tamalpais and is prominent enough to be visible to westbound drivers on the Richmond-San Rafael Bridge. Though much of the mountain is shielded from development and held as an open space preserve, its coveted peak had not previously been assured protection.
In the 1980s, as property on the mountain drew interest from real estate developers, locals formed the King Mountain Open Space Association to advocate for its conservation, according to the group's president, David Moller. The county bought and then set aside 131 acres of the mountain's lower flanks and negotiated a scenic easement over another 129 acres of private land at its higher reaches.
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Since the 1990s, people have been able to circumnavigate King Mountain via a 3.5-mile loop trail that wraps entirely around the mountain's midsection. But the broad 32-acre summit has remained privately held and off-limits. Today, it is fenced off, and a fire road leading to it is blocked by a padlocked metal gate.
The property has changed ownership several times in the past four decades. At one point, an owner garnered approvals to build a 27,500-square-foot estate and mocked up designs for an expansive, glass-walled compound to be built on top, according to real estate marketer Open Homes Photography.
In the 2020s, then-owner Omega Three Trust attempted unsuccessfully to sell the property at auction. The trust then listed it up for sale at $19 million. A website devoted to the listing and hosted by Open Homes characterized the property as a "secluded paradise" with "unparalleled privacy" and dubs it "the Bay Area's ultimate unicorn."
Moller said his group's attempts to persuade former owners to sell or transfer the land to the public never previously gained traction. "We've never been happy with the situation," he said. "We want the whole mountain for open space."
A county staff report notes that "acquisition of the property has historically been financially infeasible."
Then, six months ago, something miraculous occurred.
A philanthropic foundation based in Delaware cold-emailed Bill Long, chair of Marin Open Space Trust. He'd never heard of the Shelby Cullom Davis Charitable Fund, a nonprofit that has given hundreds of millions of dollars to support conservation and education as well as arts and culture. But a representative inquired about the process of purchasing and donating the property to the county, Long said.
"We get these kinds of inquiries and phone messages for all kinds of properties, and they rarely pan out," Long said.
After corresponding with foundation representatives, Long quickly enlisted support from Moller's group and the county to help facilitate a transfer. In April, backed by the charitable foundation, Marin Open Space Trust signed the purchase agreement with Omega Three Trust. The purchase price was not disclosed. (A Chronicle inquiry to the Shelby Cullom Davis Charitable Fund wasn't returned before press time. Omega Three Trust could not be reached for comment.)
On Tuesday, the county Board of Supervisors is poised to approve transfer of the property from the open space trust to the Marin County Open Space District, which will manage it as part of the larger King Mountain Preserve going forward.
As part of the arrangement, the foundation also agreed to contribute a $2 million endowment to cover at least a decade's worth of "restoration, invasive species management, maintenance, public access improvements and long-term conservation," according to the county.
After decades of attempts to conserve King Mountain, the suddenness and speed of the donation deal is shocking, those involved say.
"Over the course of my career, this is the first time anything like this has happened," said Chamberlain, the county parks director. He called the foundation's contribution "an extraordinary gift."
"This really came out of nowhere. Nobody was expecting this," he said. "It's been a frenzy to facilitate this transaction."
"It would have been a shame to lose that ridgetop to a single massive estate," Chamberlain added.
It's not exactly clear when the public might gain access to the mountaintop. The escrow process is due to conclude in September, Long said, at which point the open space trust will immediately transfer the property to the county.
The county has indicated excitement about allowing hikers up to King Mountain's summit. Given that there's already a fire road leading from the loop trail to the mountaintop, it might be as simple as unlocking the gate.
"A lot of people have wanted to see this property opened for a long time," Long said. "This is going to become a really popular destination."
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This story was originally published July 12, 2026 at 10:42 AM.