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Marion Mountain Trail to San Jacinto Peak

Riverside · Managed by Mount San Jacinto State Park (California State Parks) · Region: San Jacinto Mountains
Difficulty 55/100 · Strenuousout and back#10ers#peak-bagging#idyllwild#shortest-route
Distance
10.6 mi
Total gain
4,500 ft
Net gain
4,500 ft
Net loss
4,500 ft
Days
2
Permit
Required
Campfires
Campfires prohibited

Overview

The Marion Mountain Trail is the shortest route from Idyllwild to the top of the San Jacinto Mountains: 5.3 miles and 4,500 feet of relentless climbing to the 10,834-foot summit. Steeper and less traveled than Devil's Slide — a two-day push with a camp at Little Round Valley.

Highlights

  • The shortest — and steepest — Idyllwild route to the peak
  • Far fewer hikers than Devil's Slide
  • Little Round Valley camp below the summit country
  • Desert-to-alpine views from the top

How hard is Marion Mountain Trail to San Jacinto Peak?

CaliPeaks rates this route 55/100 (Strenuous). The score weights five factors: climbing counts for 45% — 4,500 ft puts this trip at 38% of the reference climb; distance 20% at 10.6 miles; maximum altitude 15% at 10,712 ft; route technicality 10% (established trail throughout); and trip length 10% at 2 days. A score under 20 suits first-time backpackers; 60+ means serious endurance. See how we score difficulty for the full method.

Logistics

  • Trailhead: Marion Mountain Trailhead (Idyllwild) · parking: Marion Mountain Campground area, north of Idyllwild
  • Water: Seasonal springs near Little Round Valley; treat all water and confirm flow.
  • Resupply: None; Idyllwild has full services.
  • Shuttle: Not needed for an out-and-back.
  • Stove required: yes — no fires possible on this route

Permits

  • Agency: Mount San Jacinto State Park (California State Parks)
  • Reserve or apply on parks.ca.gov
  • Quota: Primitive wilderness campgrounds — camping permit $5 per person.
  • Reservation window: Permits issued at the Idyllwild Ranger Station; wilderness sites are not reservable.

Campfires & stove regulations

Campfires prohibited. Campfires are prohibited in the state wilderness. Only portable stoves with an on/off switch are permitted. Current fire restrictions. Rules change with conditions — always confirm with the managing agency before your trip.

Best time to go

Best months: June, July, August, September, October.

Snow: The upper trail can hold snow into June.

Heat: Warm on the lower slopes.

Bugs: Minimal.

Weather forecast

Know before you go

  • 4,500 feet in 5.3 miles — very steep sustained climbing
  • Stoves only; campfires prohibited in the wilderness
  • Water is seasonal — carry for the upper route

Sources & citations

Data compiled 2026 from public agency and reference sources. All descriptive text on this page is original; verify current conditions with the managing agency before your trip.

  1. SRTM90 elevation data (sampled). OpenTopoData (SRTM, NASA/USGS-derived open data) via Photon geocoding (OpenStreetMap). https://www.opentopodata.org/. Accessed 2026-09-10. Elevation sampled at geocoded coordinates; location from OpenStreetMap data (ODbL).
  2. Hiking Trails — Mount San Jacinto State Park. California State Parks. https://www.parks.ca.gov/?page_id=30375. Accessed 2026-09-07. License: Public domain (US government work). Marion Mountain Trail to San Jacinto Peak (10.6 mi round trip, 4,500 ft elevation gain), rated Very to Extremely Strenuous.
  3. Mount San Jacinto State Park. California State Parks. https://www.parks.ca.gov/?page_id=636. Accessed 2026-09-07. License: Public domain (US government work). Wilderness camping permit ($5/person), campfire prohibition and stove rule, dogs prohibited.
  4. San Jacinto Peak. Wikipedia. https://en.wikipedia.org/wiki/San_Jacinto_Peak. Accessed 2026-09-07. License: CC BY-SA 4.0. Summit elevation (10,834 ft).