⏵ Course guide · Point-to-point Colorado ultra
The Grand Traverse Mountain Run sends its field 40 miles point-to-point from Crested Butte to Aspen, over 6,000 feet of climbing across the Elk Mountains on the same route used by the Grand Traverse backcountry ski race. There is no loop back to the start, no easy shortcut, and a hard finish window at Ajax Park in Aspen. I will walk you through the route and logistics first, then give you a pacing and fueling plan built for a long day at altitude with real aid gaps, plus free calculators to dial in your own numbers.
These facts come from the official Crested Butte Nordic race page. Individual aid station cutoffs are strictly enforced but published in the racer manual, not on the public site, so pull the current manual before you build a pacing plan.
This is a true point-to-point mountain ultra. You start in Crested Butte before dawn and finish in Aspen, and the only way there is over the Elk Mountains on the Grand Traverse ski route. That commitment shapes everything about how you should run it.
The Grand Traverse Mountain Run follows the exact course used by the Grand Traverse backcountry ski race, a route built for winter travel across the Elk Mountains between Crested Butte and Aspen. Running it in September strips away the snow but keeps the elevation and the remoteness, over 6,000 feet of climbing across genuine high alpine terrain with no pavement and no easy bailout once you are committed.
There are five aid stations across the 40 mile course, which is not a dense network for a race this long and this remote. Drop bags are accepted at the Taylor Pass aid station around mile 23.5 and at the finish line in Aspen, so plan what you need at that roughly two-thirds mark and pack the rest on your body. Every runner is required to carry mandatory live tracking through MAProgress, a real safety measure given how exposed and far from a road much of this route runs.
The finish line at Ajax Park in Aspen is open from noon to 6:30 PM, which off the 5:45 AM start gives you roughly 12 hours 45 minutes to get from Crested Butte to Aspen. Individual aid station cutoffs are strictly enforced along the way and vary by location, detailed in the current racer manual rather than the public page, so get that manual and know exactly where your checkpoints are before you start.
With sparse aid, real altitude, and a firm finish window, the Grand Traverse punishes anyone who treats it like a road ultra with trail scenery. Effort management from the first climb matters more here than it does on a looped course you can bail from.
Crested Butte and the high points along this route sit well above what most runners train at, and altitude does not care how fit you are at sea level. A grade-adjusted pace target keeps you honest on the early climbs, when the temptation to bank time is strongest and the cost of going out too hard at elevation shows up hours later, not immediately.
Because the finish line itself only opens at noon, arriving early does not help you, and arriving after 6:30 PM means you are out of the race. Use a vert-aware finish prediction built off your real climbing fitness to sanity check whether your training supports a comfortable finish inside that window, or whether you are cutting it closer than you think on a course with sparse aid and mandatory tracking for a reason.
⏵ Free tools to pace this course
Five aid stations over 40 miles at altitude means real gaps between resupply. Plan to carry more than you would on a better-aided course, and treat the on-course fuel as a supplement to your own plan, not the plan itself.
Aim for roughly 60 to 90 grams of carbohydrate per hour. Gnarly Hydrate and Fuel20 are provided on course as the official sponsor products, so try them in training if you plan to rely on them, but with only five stations across the route you need enough in your pack to bridge the longer gaps without running dry.
Sodium in the 300 to 700 mg per liter range covers most runners, and the sustained climbing effort at altitude on this course is a good reason to lean toward the higher end rather than the lower one. Dial this in during training at elevation if you can, since sea-level sweat rates are a poor guide for a course that spends most of the day well above 9,000 feet.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and a long day at Colorado altitude with the free ultra fueling calculator. Browse the rest of the free running tools at the tools hub.
⏵ Train for it with Summit Line
Get a race-day plan built around YOUR fitness, this exact point-to-point Elk Mountains climbing profile, and a real finish estimate against the Ajax Park window. Summit Line reads your real training, builds a plan for sustained mountain climbing at altitude, and rehearses your fueling so race day is something you execute, not guess at.
It is a serious point-to-point mountain ultra. Forty miles from Crested Butte to Aspen over the Elk Mountains, following the same route as the Grand Traverse backcountry ski race, with over 6,000 feet of climbing at altitude the whole way. There is no loop to bail out on and no easy out once you are past the early aid stations, so this is a race that rewards real mountain fitness and honest pacing over raw speed.
The official page lists over 6,000 feet of elevation gain across the 40 mile point-to-point route. That climbing is spread across the Elk Mountains between Crested Butte and Aspen rather than stacked into one obvious crux, so expect sustained work at altitude for most of the day rather than a single defining climb.
With a finish window that runs from noon to 6:30 PM off a start before 6 AM, most runners are looking at somewhere in the 7 to 12 hour range at altitude. Aim for roughly 60 to 90 grams of carbohydrate per hour, and keep sodium in the 300 to 700 mg per liter range, adjusting up if the day runs warm through the lower valley sections. Gnarly Nutrition is the official hydration and fuel sponsor and provides Gnarly Hydrate and Fuel20 on course, but five aid stations across 40 miles at altitude is not dense, so plan real self-sufficiency between stops rather than counting on frequent resupply. Build your numbers with the free ultra fueling calculator before race day.
The official page confirms the finish line at Ajax Park in Aspen is open from noon to 6:30 PM, which works out to roughly 12 hours 45 minutes from the 5:45 AM start. Individual aid station cutoffs along the route are strictly enforced and vary by location, but the exact times are published in the racer manual rather than on the public site, so pull the current manual before race day and build your pacing plan around it.
The course crosses the Elk Mountains between Crested Butte and Aspen on the same route used by the Grand Traverse backcountry ski race, so expect high alpine terrain, real elevation, and weather that can shift fast even in early September. Mandatory live tracking is required for every runner, which tells you how seriously the organizers treat the exposure and remoteness of this route.
Not as a first ultra. Forty miles with over 6,000 feet of gain at altitude, a point-to-point route through remote terrain, and a roughly 12 hour 45 minute window is a demanding day even for experienced mountain runners. If you have completed shorter Colorado mountain ultras and trained specifically at altitude, the Grand Traverse is a reasonable next step. If this would be your first time above 30 miles, look for something with more aid density and an easier bailout first.
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<a href="https://runsummitline.com/guides/grand-traverse-mountain-run">The Grand Traverse Mountain Run course guide</a>This guide is independent and for planning only. The course details, dates, cutoffs, and aid stations come from public sources and can change year to year, so confirm the current specifics with the official race before you register or run. The fueling and pacing advice is general and not medical advice.