Humber Park / Devil's Slide (Idyllwild)
Two different pieces of paper, and the permit is the harder one. Parking at Humber Park (end of Fern Valley Rd, ~6,400 ft) needs an Adventure Pass — but hiking Devil's Slide also needs a separate free San Jacinto Wilderness day-use permit, capped at 30 per day on summer weekend days (Sat–Sun, Memorial Day–Labor Day). Roadside on Fern Valley Rd is signed no-stopping and tows are real. The permit-free fallback from the same lot: the Ernie Maxwell Scenic Trail.
The facts
- Trail served
- Devil's Slide 3E05 → Saddle Junction, Tahquitz Peak, San Jacinto high country; Ernie Maxwell Scenic Trail (no permit)
- Cost / pass
- Adventure Pass ($5/day, $30/yr) or Interagency pass to park; Devil's Slide wilderness permit is free but required
- Lot size
- Two paved sections (lower + upper); no official space count published
- When it fills
- Summer weekends: hikers report arriving at sunrise; the 30-permit quota usually binds before the lot does
- Overflow option
- None sanctioned — Fern Valley Rd is signed no-stopping; downtown Idyllwild is ~2 mi away
- Tow / citation risk
- High — documented tows off Fern Valley Rd/lower Humber Park (~$440 to Idyllwild Garage); citations ~$114
- Restrooms
- Yes
- Road to the lot
- Paved Fern Valley Rd from downtown Idyllwild (~5 min); Hwy 243 approach has construction flag delays into winter 2026
- Busy season
- May–October; quota applies Memorial Day–Labor Day weekends
Getting there
24559 Fern Valley Rd, Idyllwild, CA 92549
Get directions →The paperwork stack
Humber Park is the most rule-stacked trailhead we cover, and people get burned by treating it as one requirement instead of two. To park: an Adventure Pass (or Interagency pass) on the dash — buy it in town, not at the lot. To hike Devil's Slide: a separate, free San Jacinto Wilderness day-use permit from the ranger station at 54270 Pine Crest Ave in Idyllwild — a self-issue kiosk outside the office covers non-quota days 24/7.
The crunch is summer weekends: Saturdays and Sundays from Memorial Day through Labor Day, Devil's Slide is capped at 30 day-use permits per day. Reserve up to 90 days ahead by phone — (909) 382-2921 — or take your chances same-day. Rangers check at the trailhead on quota weekends. On those days the permit, not the parking, is usually what ends people's plans.
Parking reality and the tow trucks
The lot itself is paved, in two sections (lower by the Ernie Maxwell trailhead, upper by the restrooms and Devil's Slide), at about 6,400 ft at the end of Fern Valley Road. No official space count is published, so we won't invent one — hiker consensus is simply that summer weekend mornings demand a sunrise arrival.
Do not improvise on Fern Valley Road: it's signed no-stopping near the park entrance with seasonal no-parking below, and climbers' forums document tows off the road and even the lower lot — roughly $440 to retrieve your car from town, with citations around $114. There is no sanctioned overflow; downtown Idyllwild is about two miles back down the road.
The permit-free plan B
If the quota's gone or the day got away from you, the Ernie Maxwell Scenic Trail leaves from the same lot's lower section: ~2.6 miles one-way of shaded forest toward town, no wilderness permit required per the Forest Service's San Jacinto district trail brochure (one USFS webpage says otherwise — the brochure and every practical source disagree; call (909) 382-2921 if you want it from the horse's mouth). The Adventure Pass still applies to the lot either way.
One more 2026 note: Highway 243 into Idyllwild has an active Caltrans paving project with 15–20 minute flag delays into winter — budget for it.
Frequently asked questions
Do you need a permit for the Devil's Slide Trail?
Yes — a free San Jacinto Wilderness day-use permit from the Idyllwild ranger station (self-issue kiosk on non-quota days). On summer weekend days (Sat–Sun, Memorial Day–Labor Day) it's capped at 30 permits per day; reserve up to 90 days ahead at (909) 382-2921.
Where do you park for Tahquitz Peak?
Humber Park at the end of Fern Valley Road in Idyllwild — Tahquitz Peak is reached via Devil's Slide to Saddle Junction, so the same Adventure Pass and wilderness-permit rules apply.
Do you need an Adventure Pass at Humber Park even without entering the wilderness?
Yes. The Adventure Pass covers the parking itself and applies whichever trail you hike. It's separate from the wilderness permit and isn't sold at the lot — buy it in town first.
What happens if you park on Fern Valley Road?
The stretch near Humber Park is signed no-stopping with seasonal no-parking below, and enforcement is real — documented tows run about $440 plus a citation. If the lot is full, there is no sanctioned overflow.
Facts on this page last verified July 18, 2026. Fees, hours, and access rules change seasonally — confirm with the official source before a long drive.