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Mt. Disappointment Mountain Race Course Guide

The Mt. Disappointment Mountain Race is a hard, lung-busting trail race in the San Gabriel Mountains above Los Angeles, and it does not let up. Big sustained climbs, rocky technical singletrack, real late-September heat down in the canyons, and a final climb up the Kenyon Devore Trail to the Mt. Wilson summit that will test you. I will walk you through the course, then give you pacing and fueling strategy built for exactly those conditions, plus free tools to dial in your own numbers.

⏵ Quick facts

The race at a glance

Date
Sat, September 26, 2026, 7:00 AM start
Location
San Gabriel Mountains, Angeles National Forest, CA
Start / Finish
Mt. Wilson Skyline Park, near Sierra Madre, about 45 min from LA
Distances
25K, 50K, and a 60K in some years
Elevation gain
About 3,800 ft (25K) and about 7,000 ft (50K)
Cutoffs
25K about 5 hours, 50K about 10 hours
Terrain
Mostly singletrack, rocky and technical, plus fire road
Qualifier
No major-series qualifier status published

Note: distances offered vary by year, the 25K and 50K are the core events and a 60K has been part of the lineup in some editions. The 60K vert and aid layout are not separately published, so this guide stays general on those. Always confirm the date, exact distances, course, aid stations, and cutoffs on the official race site before you plan your race.

The course

The race runs through the San Gabriel Mountains in the Angeles National Forest, starting and finishing at Mt. Wilson Skyline Park at the summit of Mt. Wilson. It stitches together historic Angeles trails, the Gabrielino, Colby Canyon, and Strawberry Peak among them, on mostly technical singletrack with rocky sections, steep climbs, and fast descents through pine forest and chaparral canyon. The 50K packs about 7,000 feet of climbing into 31 miles, and the 25K about 3,800 feet into 15.5 miles.

A point-to-point feel that always returns to the summit

The course drops off the high country around Mt. Wilson into the canyons and then has to climb back out, so the elevation profile is a series of long descents paired with long, grinding ascents rather than rolling terrain. You spend the day either working hard uphill or managing rocky technical downhill, with very little flat. That rhythm is the whole character of the race.

Because the start and finish both sit at the Mt. Wilson summit, the lowest, hottest point of your day comes in the canyons in the middle of the course, and you climb away from it when you are already tired. Plan your effort knowing the hardest work is back-loaded, not front-loaded.

The Kenyon Devore climb decides the race

The defining feature of the 50K is the final ascent of the Kenyon Devore Trail back up to the Mt. Wilson summit, a steep, sustained climb of roughly 1,900 feet in about 3 miles that runners routinely describe as the longest few miles of the day. This is where the race is won or lost. People who spent too much energy early, or who fell behind on fuel and fluids in the heat, watch the wheels come off here.

Run the first three quarters of the course with this climb in mind. The goal is to reach the base of Kenyon Devore with working legs and a topped-off stomach, so you can power-hike it steadily instead of stopping every switchback. Treat everything before it as setup for this climb.

Heat, exposure, and the canyon descents

Late September in the San Gabriels can be hot, and the hottest part of the day tends to land on the long canyon descents toward the low point of the course, exactly where there is little shade. Reports from this race have documented canyon temperatures climbing well into the 90s and beyond. Heat and dehydration, not raw fitness, are the most common reasons runners fade or miss cutoffs here.

The descents are also rocky and technical, so the downhills are not free speed, they are quad-pounding and demand attention. Run them controlled and light early so you still have brakes for the later descents, and keep drinking and salting through the hot canyon miles even when your appetite drops.

Aid stations and cutoffs

Per the official race information, the 50K is supported by five fully stocked aid stations and the 25K by two, with the Red Box area serving as a notable crew and family access point. Josephine Saddle is another landmark on the course. Carry enough between stations to cover the exposed canyon stretches in the heat.

The overall cutoffs are about 5 hours for the 25K and about 10 hours for the 50K from the 7:00 AM start, with aid station cutoffs along the way. Because the Kenyon Devore climb comes last, build your plan to reach the final aid station with a real time buffer. Always confirm the current cutoff chart on the official race site before you race.

Pacing strategy for Mt. Disappointment

A climbing-heavy, hot course with its biggest climb at the end rewards patience and punishes ego. Pace this race by effort and by grade, not by the flat-ground numbers from your home training runs.

Pace the climbs by grade, not by clock

On a course with up to 7,000 feet of gain in 31 miles, your moving pace will swing wildly between the long climbs and the technical descents, and that is correct. Power-hike the steep pitches efficiently and run only the grades you can run without spiking your heart rate. Trying to hold a steady minutes-per-mile number across this terrain is the fast way to blow up before Kenyon Devore.

Use our free grade-adjusted pace calculator to translate your flat fitness into honest effort targets for the steep San Gabriel climbs, so you know whether you are pacing the vertical sustainably or burning matches you will need on the final ascent.

Save your legs for the final climb

The single best pacing decision on this course is to arrive at the base of the Kenyon Devore climb with energy left. That means holding back on the early descents, running them controlled rather than letting gravity hammer your quads, and keeping your effort honest through the hot canyon middle. The runners who finish strong are the ones who can still march uphill at mile 28.

To set a realistic finish goal that actually accounts for all that vertical, use our vert-aware race time calculator. It factors the climbing into your projected finish so you are not anchored to a flat-course estimate that the San Gabriel Mountains will quietly demolish.

Build your plan backward from the cutoffs and the heat

With an overall cutoff near 10 hours for the 50K and the hardest climb saved for last, pace the early miles to bank time before the heat of the day peaks in the canyons. Then expect to slow on the final climb and plan for it. A reverse-engineered split plan beats running on feel and hoping the math works out at the summit.

If you want to know how your fitness from a recent race translates to this mountain effort, our race equivalent calculator helps you reality-check your goal time before you commit, and our race time calculator turns it into split targets that respect the vert.

Fueling strategy for Mt. Disappointment

A hot, exposed, climbing-heavy effort makes fueling and hydration as decisive as fitness. The canyon heat in late September is the variable that wrecks most well-trained runners, so plan for it.

Carbs: ramp to the high end, on a trained gut

For an effort this long, target roughly 60 to 90 grams of carbohydrate per hour, leaning toward the high end once your gut is trained to handle it. Use a glucose-plus-fructose blend so you can absorb more than a single sugar allows, and rehearse your exact hourly carb number on long climbing runs so it feels routine, not experimental, by race day.

The heat makes this harder, because a hot stomach tolerates less. That is one more reason to practice fueling in race-like heat and to keep taking in calories through the hot canyon hours, when your appetite drops but your engine still needs fuel for the climb home.

Sodium and fluid: built for the canyon heat

In the exposed San Gabriel canyons, sweat losses can be high, so bias your sodium toward 500 to 700 mg per liter of fluid and carry enough to cover the long, hot gaps between aid stations. Cramping, a sloshy stomach, and that wrung-out late-race feeling on Kenyon Devore are usually fluid and sodium balance problems, not fitness problems.

Dial in a personalized plan with our free ultra fueling calculator: enter your weight, your goal time, and the expected heat, and it gives you a carb, sodium, fluid, and caffeine prescription per hour built for this race duration and conditions. Then go test it on a hot training run.

⏵ Free calculators for this race

Run your Mt. Disappointment numbers with our free, no-signup tools, then let Summit Line tie them all to your real fitness and this exact course.

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Train for the terrain

This race is decided by your climbing legs, your heat tolerance, and your fueling. These free guides go deep on each, with the right depth for a 25K, 50K, or 60K in the San Gabriels.

⏵ Train for Mt. Disappointment

Get a race-day plan dialed to YOUR fitness and this exact course. Summit Line reads your actual training, builds a fueling and pacing plan around the San Gabriel climbing and the canyon heat, and tracks how your gut and legs handle the load so the Kenyon Devore climb is rehearsed, not guessed.

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Mt. Disappointment Mountain Race FAQ

How hard is the Mt. Disappointment Mountain Race?

It is one of the harder trail races in Southern California for the distance, and you should treat it that way. The 50K stacks about 7,000 feet of climbing into 31 miles of mostly technical singletrack high in the San Gabriel Mountains, and it ends with the long Kenyon Devore climb back up to Mt. Wilson. The 25K is no warmup either, about 3,800 feet of gain in 15.5 miles. Late September in the Angeles National Forest gets hot and there is no shade in the canyons, the descents are rocky and they wreck your quads, and the cutoffs are firm. This is a real mountain race. It rewards strong climbing legs and people who handle the heat, and it punishes everyone else.

How much climbing is in the Mt. Disappointment Mountain Race?

The 25K carries about 3,800 feet of gain across 15.5 miles, and the 50K carries about 7,000 feet across 31 miles, per the official race information. When a 60K is on the schedule it adds even more, though the organizers do not publish a verified vert number for that one, so do not quote me on it. Either way the climbing does not spread out evenly. It comes in long sustained pushes on trails like the Gabrielino, Colby Canyon, and Strawberry Peak, and then it ends with the steep final climb up the Kenyon Devore Trail to the Mt. Wilson summit.

How should I fuel for the Mt. Disappointment Mountain Race?

Fuel it like the hot, climbing-heavy day it is. Most runners go for about 60 to 90 grams of carbohydrate per hour, leaning toward the high end if your gut is trained for it, and a sodium concentration around 500 to 700 mg per liter of fluid because those San Gabriel canyons get hot in late September. Carry enough fluid to cover the gaps between the aid stations, and pay extra attention on the exposed canyon descents where the heat is worst. And practice your hourly carb number in training first, do not figure it out on race day. Our free ultra fueling calculator builds you a carb, sodium, and fluid plan per hour for the expected duration and heat.

What are the cutoffs for the Mt. Disappointment Mountain Race?

Per the official race information, the 25K has an overall cutoff of about 5 hours and the 50K has an overall cutoff of about 10 hours from the 7:00 AM start, and there are aid station cutoffs along the way that keep slower runners moving. Here is the thing. The course saves its hardest climb for last, on the Kenyon Devore Trail, so you want to hit the final aid station with real time in the bank. Build your pacing plan backward from the cutoffs and leave yourself a buffer. And always confirm the current cutoffs on the official race site before race day.

Where is the Mt. Disappointment Mountain Race held?

It runs in the San Gabriel Mountains inside the Angeles National Forest, and you start and finish at Mt. Wilson Skyline Park at the summit of Mt. Wilson, up by the observatory above the town of Sierra Madre and about 45 minutes from Los Angeles. The course strings together Angeles trails like the Gabrielino, Colby Canyon, and Strawberry Peak. The Red Box area is the spot where your crew and family can meet you.

Is the Mt. Disappointment Mountain Race a Western States or UTMB qualifier?

The organizers do not publish major-series qualifier status (Western States, UTMB, Hardrock, or Cocodona) for this race, so do not count on it as a qualifier. People run it for the challenge, the classic San Gabriel terrain, and because it is one of the most demanding 50K courses in the Los Angeles area, not for a qualifying slot. And always verify current qualifier policies straight from the race and the series you are chasing.

This guide is for planning and training purposes and reflects publicly available information about the Mt. Disappointment Mountain Race. Race details, including the date, distances offered, course, aid stations, and cutoffs, can change year to year. Always confirm the current specifics on the official race website before you train or travel.