Every regular at Trione-Annadel has one: a cut-through past the Cobblestone fork, a faint spur off Steve's 'S' Trail, a route that saves ten minutes and shows up on nobody's map. Oakmont hikers have walked these paths for decades without a second thought. What most of them don't know is that California State Parks has already reviewed their shortcut, given it a formal ruling, and posted the reasoning online for anyone to read.
That ruling comes from the park's Non-System Route Evaluation Explorer, a tool built as part of the long-awaited Road and Trail Management Plan for Trione-Annadel. The plan itself is expected to reach its Proposed Draft stage this month, but the individual verdicts on unofficial trails have been public for a while. If you've got a favorite social trail, you can already look up whether the state plans to keep it, formalize it, or shut it down.
Nearly Half the Park's Trails Were Never Official
Trione-Annadel has 45 miles of designated trail. It also has roughly 40 miles of unofficial routes woven through the same terrain, worn in by decades of hikers, cyclists, and equestrians who found their own way around. That's not a rounding error. It means close to half of what people actually walk in this park was never sanctioned in the first place.
Some of these social trails date back to the property's ranching days, or to its stint as a source of cobblestones for San Francisco's streets. Others are simply the paths people made because the official route was crowded, muddy, or slower than it needed to be. Redwood Trail Alliance executive director Tom Boss, whose nonprofit builds and maintains multi-use trails across the North Bay, has described the park as almost urban in how much use it absorbs for its size. Trione-Annadel takes in up to 13,000 visitors a month, and the wear shows in specific places: the state's February 2026 field survey found sections of the Cobblestone Trail where repeated foot and tire traffic has stripped away topsoil, exposing rock and roots and carving channels that now direct rainwater straight down the path instead of off to the side.
That kind of damage is exactly what the new plan is meant to address, and it's why the reviewers didn't stop at deciding whether a social trail should exist. They asked whether it should exist there, on that slope, in that soil.
What the Plan Actually Proposes
The draft, now in the eighth of nine steps required for approval, splits the park into five planning zones: Cobblestone, Richardson, Lawndale, Schultz, and Bennett. Within those zones, the recommendations include:
- Separating bike-only and hike-only sections on routes where the two uses currently collide
- Legalizing a handful of well-used social trails, including the path to Henry's Knob
- Decommissioning routes flagged as unsustainable, particularly ones built on a straight fall-line grade that erodes quickly
- Adding digital fee kiosks at trailheads, since much of the park currently has no way to collect the day-use fee from walk-in visitors
- Funding trail renovations in the most worn sections, starting with Cobblestone
Henry's Knob is the plan's most talked-about case. It sits at 1,525 feet near the park's southwest corner, reachable only by unsanctioned routes, and it's one of the more sought-after views in Trione-Annadel despite being technically off-limits. The name has nothing to do with Henry Trione, the philanthropist whose family the park is named for. It comes from Henry Szostak, a longtime leader of the Oakmont Hikers, who was memorialized by the club after his death in February 2004. Two decades later, hikers are still climbing to the spot named for him on trails the state never approved, and the new plan would finally make that legal.
Not everyone treats the unofficial routes the same way in the meantime. Don McCullough, president of Friends of Trione-Annadel, has said he stays off Henry's Knob himself, even though he'd like to see it, because he prefers not to add wear to a route the park hasn't sanctioned yet. It's a small thing, but it's the kind of local restraint that keeps a place like this from eroding faster than it can heal.
The Work That's Already Happening
While the plan works through its final approval steps, the on-the-ground repairs haven't waited. Friends of Trione-Annadel, a 501(c)(3) founded in 2017, has already funded major upgrades to the Lawndale Trailhead in 2024 and to the Channel Trail in 2025. The group repaired the bridge where Spring Creek and Canyon trails meet, commissioned a study on whether spotted owls nest in the park (the results cleared the way for heavier equipment to be used in trail repairs), and has installed four bike repair stations across the park in an effort that's still ongoing this year. In 2025 alone, volunteers logged fifteen organized workdays maintaining trails, with more scheduled for 2026. Since 2021, the group has also transported more than 1,000 Santa Rosa schoolchildren into the park for field trips.
None of that required the state's plan to be finalized first. It's a reminder that the RTMP isn't creating momentum from nothing. It's catching up to work that local volunteers were already doing.
Where Oakmont Fits Into All of This
The Oakmont Hiking Club runs its outings straight out of the Berger Center parking lot, sorting members into short, intermediate, and long groups that each coordinate through the club's own private forums. A typical spring week might list an intermediate hike crossing from Spring Lake into Trione-Annadel, or a long hike out to Canyon, the waterfall, and Pony Gate, covering seven miles with real elevation gain. These aren't casual strolls. They're structured, recurring outings that treat the park as an extension of the neighborhood rather than a destination you drive to.
That's part of why the RTMP matters here in a way it might not to someone visiting from outside the county. The trail names in the plan, Cobblestone, Rough-Go, Channel, Steve's 'S', Warren Richardson, aren't abstractions. They're the same names on the sign-up sheets at the Berger Center every week. When the state decides which social trails survive and which get closed, it's deciding the actual route your Tuesday hike will follow next year.
What To Actually Do With This
If you have a regular route through the park that veers off the official map, it's worth five minutes to look up its status in the Non-System Route Evaluation Explorer before you assume it'll still be there. Some routes are being recommended for full legalization. Others, especially the ones built straight down a slope, are flagged for closure regardless of how long people have been using them.
If you're picking a hike this month, Cobblestone's most eroded stretches are worth avoiding after rain until the renovation work reaches that zone. And if you've ever wondered who funds the quieter improvements around the park, the bike repair stations, the rebuilt bridge at Spring Creek, the work is largely coming from Friends of Trione-Annadel, which still runs volunteer workdays open to residents who want to put in a few hours.
The state's own timeline points to a Proposed Draft release this August, with a final version possible by the end of summer if the review process holds. Whatever your favorite unofficial trail is, its fate was probably already decided months ago. It's just sitting in a database most hikers haven't thought to check.
If you're weighing a move into Oakmont and want a clearer sense of what daily life looks like here, from the trail network to the club calendar, Kaitlin Karkos can walk you through the neighborhood at whatever pace makes sense for you. Let's Connect.
