Bighorn Trail Run Course Guide

The opening climb: out of Tongue River Canyon, do not race it

The 100 starts in the heat of a Friday afternoon and goes straight up out of Tongue River Canyon into the high country, with the early Dry Fork Ridge checkpoint around mile 13.5 and a real cutoff waiting there. This first big climb is where impatient runners cook themselves. It feels fine in the first few miles because you are fresh and the energy is high, but you have a very long way to go, so hike the steep stuff and keep your effort honest.

The reward up top is the high country: alpine meadows, pine and granite, big open views. The footing is rugged and the altitude is real, with the course living up near and above 8,000 feet for long stretches. Treat the early miles as setup, not as a place to make time, and you will still have legs when it counts.

The descent to Sally’s and the long climb to Jaws

After the high country the course drops a long way down to Sally’s Footbridge around mile 30 at about 4,590 feet, and that descent is fast and quad-eating if you are careless with it. Then you turn and grind back up toward the Jaws turnaround near mile 48 at about 8,800 feet, which is the high, remote heart of the race. This is the section where the night, the altitude, and the climbing all stack up at once.

Hitting Jaws is a milestone, but it is only halfway, and the way you feel coming in tells you a lot about how the rest goes. Get in, take care of yourself, change socks if your feet are wrecked, eat real food, and get back out. Lingering too long at the turnaround in the cold is a classic way to seize up and lose the will to move.

The return: the famous descent and the wheels-fall-off miles

The way back is a huge net descent off the high country, and the long drop down through the canyon late in the race is where Bighorn is truly won and lost. Miles and miles of downhill on tired, beat-up quads, often in heat by the time you are back down low, is what turns a strong day into a death march. If you trained the descents and paced the front half, you can still move here. If you trashed your legs early, these miles become a slow, painful shuffle to Dayton.

Practice long, controlled, runnable descending before race day, on rough ground, when you are already tired. Being able to keep your legs turning over downhill at mile 80, with your quads shredded, is honestly the single skill that separates finishers from the people the cutoffs catch.

Mud, water, and the conditions that define the year

June in the Bighorns is wild-card weather, and conditions can make this course a completely different race year to year. Expect lingering snow patches up high, creek and river crossings that can run knee-deep with cold snowmelt, and the mud the race is famous for. A wet year turns long stretches into a slick, sucking slog that destroys your splits and your feet. A dry, hot year punishes you down low in the canyons instead.

Plan for all of it. Carry or stash warm layers and a reliable headlamp with backup for the cold high-country night, expect wet feet and manage them with drop-bag socks, and do not let a fast forecast lull you into packing light. The mountains here do what they want.

The shorter races: 52, 32, and 18 mile

If you are not ready for the full 100, the 52, 32, and 18 mile races run on Saturday and share the same rugged high country, with less total vert but the same technical footing, altitude, and weather risk. The 52 in particular is a serious mountain ultra in its own right, and it makes a great stepping stone toward the hundred. None of these are easy, so treat the climbs, the descents, and the June conditions with the same respect even on the shorter distances.

Pace the climbs by grade, not by the watch

Your flat-ground pace is meaningless on the long Bighorn climbs. What matters is grade-adjusted effort, so hold a steady output you can sustain up the grade and hike the steep pitches without guilt. The mistake here is running the early climb out of Tongue River Canyon too hard because it feels easy, then paying for it across the rest of the day. Use a grade-adjusted pace to turn your real fitness into honest climbing and descending targets, and you will not blow up before Jaws.

Build a vert-aware finish prediction and back into the cutoffs

Do not guess your Bighorn finish off a road time. The 20,500 feet of climbing, the technical footing, the altitude, and the night all add real hours. A vert-aware finish prediction that accounts for this course’s climbing gives you a realistic window, and from there you can work back into the 35-hour limit and every intermediate cutoff. Knowing your honest split into Dry Fork, Sally’s, and Jaws ahead of time means you know exactly how much buffer you have instead of finding out the hard way at night.

Carbs: steady, trained, and easy to get down at hour 20

For a day this long, aim for around 60 to 90 grams of carbohydrate per hour, and only push the higher end if your gut is trained for it. The hard part of a hundred is not the math, it is still eating when you are nauseous, cold, and tired in the middle of the night. Keep intake steady and simple, lean on real food at aid stations when gels stop going down, and rehearse your exact race-day carb rate on long back-to-back training runs so it feels automatic, not like an experiment.

Sodium and fluid: plan for the heat, the cold, and the gaps

The valleys can be hot and the high country can be near freezing, so your fluid and sodium needs swing a lot across the day. In the heat, lean toward the high end on sodium, often around 500 to 700 milligrams per liter of fluid, and more if you are a heavy or salty sweater. Carry enough to get across the long, remote stretches between aid instead of rationing and showing up empty. Weigh yourself before and after a hot long run to find your real sweat rate, then build your plan around your own number rather than a generic one.