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⏵ Course guide · Colorado ultra

Sheep Mountain Trail Runs Course Guide

The Sheep Mountain Trail Runs is a Human Potential Running Series high-altitude ultra outside Fairplay, Colorado, up in the Mosquito Range above South Park, and it earns its reputation honestly: an average elevation over 10,600 feet, billed as the second highest 50 miler in the US after San Juan Solstice. I will walk you through the course first, then give you a pacing and fueling plan built for the thin air and the long day. There are free calculators along the way to dial in your own numbers.

⏵ At a glance

Sheep Mountain Trail Runs quick facts

Date
Saturday, August 1, 2026 (HPRS, typically the first Saturday of August)
Location
Town of Fairplay Beach, Fairplay, CO, in the Mosquito Range above South Park (Park County)
Distances
50 Mile (runs long, around 51 mi), 50K (about 32 mi), and Half Marathon
Elevation gain
50 Mile: about 9,600 ft · 50K: about 6,200 ft · average elevation over 10,600 ft
Start
50 Mile and 50K at 6:00 AM MDT · Half Marathon at 8:00 AM MDT
Cutoff
16-hour overall limit for the 50 Mile and 50K, with aid-station cutoffs along the way
Qualifier
No Western States, Hardrock, or UTMB qualifier status listed by the race

These facts come from the official race site and UltraSignup. Check the current date, cutoffs, and aid stations in the race-day details before you commit. Race logistics change year to year.

The course: where Sheep Mountain is won and lost

The 50 mile is a lollipop loop where the first and last stretches are shared, then one big loop out over and around Sheep Mountain, Sheep Ridge, and Round Hill before you retrace your way home. It is run on flowing dirt county roads, USFS forest service and fire roads (some rocky), and singletrack, with roughly 9,600 feet of gain. The 50K is a shorter version of the same high country with about 6,200 feet of climbing. The number that actually defines this race is the average elevation: over 10,600 feet, basically the whole day.

The altitude is the real climb

Most course guides start with the biggest hill. Here the headline is that there is barely any low ground at all. You start at altitude and you stay there, rolling and climbing across exposed high country for the entire race, which means the thin air taxes every single mile, not just the steep ones. A grade that you would jog without a thought near sea level becomes a hike up here, and your top-end pace on the runnable roads is capped no matter how fit you are.

So the way to think about Sheep Mountain is not "save it for the big climb." It is "respect the altitude from the first step." The runners who blow up are usually the ones who treated the early miles like a normal 50 and spent energy they could not get back in air this thin.

The loop: Sheep Mountain, Sheep Ridge, Round Hill

Once you are off the shared section, the main loop takes you up and over Sheep Mountain, along Sheep Ridge, and around Round Hill on a mix of forest service roads and singletrack. This is the heart of the day and the most remote part of the course, with big open views of the surrounding 14ers and very little shelter. Some of the aid stations out here sit in places that are hard for even the volunteers to reach, so the gaps between support can be long.

Run this section by effort, not ego. The footing on the roads is generally runnable, the singletrack can get rocky, and the wind and sun are constant companions above treeline. Keep climbing steadily, keep eating, and do not let the open, runnable-looking terrain trick you into spending too much.

The way home: the shared miles back to Fairplay

After the loop you rejoin the shared lollipop stem and head back toward Fairplay Beach the way you came out. By now your legs know exactly how much altitude they have been breathing, and this is where a smart early pace pays off. If you ran the front half with discipline you can keep moving here, picking off the miles back to town. If you overcooked the high loop, these closing miles turn into a long, slow grind.

The finish is back down at the Town of Fairplay Beach where you started. It is not a dramatic summit finish, it is a steady return, and getting there with something left in the tank is the whole game on a course this high.

Pacing strategy for a 10,600 ft average elevation ultra

With about 9,600 feet of gain in the 50 mile and the whole course sitting above 10,600 feet, Sheep Mountain is an effort-management race, not a pace-chart race. Plan to go out slower than feels right and protect the back half.

Pace by effort and grade, not your flat splits

Your road pace is fiction up here. What matters is grade-adjusted effort with an honest discount for altitude, so hold a steady output you can sustain and hike the steeper pitches without guilt. The classic mistake is running the early runnable roads at a pace that feels easy at the start but is quietly too rich for the air, then fading hard once the altitude debt comes due. Use a grade-adjusted pace to turn your real fitness into honest climbing and descending targets, then back those off a notch for the thin air.

Build an altitude-aware finish window

Do not guess your Sheep Mountain finish from a lower-elevation 50 mile time. The 9,600 feet of climbing plus an average elevation over 10,600 feet add real hours, which is why mid-pack runners often land between 13 and 15 hours against the 16-hour limit. A vert-aware finish prediction that accounts for this course profile gives you a realistic window and lets you work back into the aid-station cutoffs, so you know how much buffer you actually have at each one instead of finding out the hard way.

⏵ Free tools to pace this course

  • Grade-adjusted pace calculator to turn your flat fitness into honest targets for the climbs and the runnable high-country roads.
  • Race-time calculator for a vert-aware finish prediction on this course’s climbing, so you can plan against the 16-hour limit and the cutoffs.
  • Race-equivalent calculator to turn a recent race result into a Sheep Mountain goal you can actually hold at altitude.

Fueling strategy for thin air and a long day

Most runners are out on the Sheep Mountain 50 mile for 13 to 15 hours, much of it above 10,600 feet, with some aid stations sitting in remote spots. That makes carbohydrate, sodium, and fluid every bit as important as fitness, and altitude makes eating harder.

Carbs: steady, easy, and trained

For a 13 to 15 hour effort, aim for around 60 to 90 grams of carbohydrate per hour, and only push the higher end if your gut is trained for it. Altitude is the catch: it tends to kill your appetite and slow your stomach, so the bigger risk here is under-eating, not over-eating. Keep the rate steady and lean on things that go down easy when you are breathing hard. Practice your exact race-day carb plan on long runs, ideally at elevation if you can get there, so the numbers feel routine instead of like an experiment on race day.

Sodium and fluid: cover the remote gaps

The high country can be warm, dry, and windy, all of which pull fluid and salt out of you faster than you notice. Take in sodium steadily, more if you are a heavy or salty sweater, and drink to thirst rather than forcing or rationing. Because some aid stations are remote and the gaps between them can be long, carry enough food and fluid to get yourself across instead of arriving empty. Weigh yourself before and after a hot long run to find your real sweat rate, then build the plan around your own number.

⏵ 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 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 Sheep Mountain course profile, and your projected splits. Summit Line reads your real training, builds a plan for the climbing and the altitude, and rehearses your fueling so race day is something you execute, not guess at.

Start free →Explore the demo

Sheep Mountain Trail Runs FAQ

How hard is the Sheep Mountain Trail Runs 50 mile?

It is one of the harder 50 milers in the country, mostly because of where it sits. The course runs at an average elevation over 10,600 feet, which the race bills as the second highest 50 miler in the US behind San Juan Solstice, and it stacks roughly 9,600 feet of climbing into a lollipop loop over and around Sheep Mountain, Sheep Ridge, and Round Hill. The thin air turns a moderate grade into hard work and shrinks your usable pace all day. The 16-hour limit is generous on paper, but mid-pack runners often take 13 to 15 hours, so this is a long day on your feet.

How much climbing and elevation is in the Sheep Mountain 50 mile?

The 50 mile has roughly 9,600 feet of total elevation gain, and the 50K has about 6,200 feet. What sets this race apart is not one giant climb, it is that the whole thing sits up high, with an average elevation over 10,600 feet across the course. You spend the day rolling and climbing on dirt county roads, forest service roads, and singletrack with very little of it at low altitude, so the gain hits harder than the same number would somewhere closer to sea level.

How should I fuel for the Sheep Mountain Trail Runs?

Treat it as a long, high-altitude effort, often 13 to 15 hours for the 50 mile, and plan to eat steadily from the start. Most runners do well on roughly 60 to 90 grams of carbohydrate per hour, but altitude tends to blunt your appetite and slow your stomach, so favor foods and drinks that go down easy and keep the rate honest instead of waiting until you feel bad. Sodium matters too, especially since the days can be warm and dry up there. Some of the aid stations are in remote spots, so carry enough food and fluid to cover the gaps. Run your own numbers with the free ultra fueling calculator.

What are the cutoff times for the Sheep Mountain 50 mile and 50K?

Both the 50 mile and the 50K carry a 16-hour overall time limit, with cutoffs at aid stations along the course so you cannot bank all your buffer for the end. The half marathon is a shorter morning event and is not run against the same long cutoff. Because some aid stations sit in remote, hard-to-reach places, confirm the exact intermediate cutoffs in the current race-day details before you start.

What is the terrain and weather like at Sheep Mountain?

The course is a lollipop loop where the first and last stretches are shared, run on flowing dirt county roads, USFS forest service and fire roads (some of it rocky), and singletrack, all at high altitude in the Mosquito Range. It is runnable in plenty of places but remote and rugged, with big views of nearby 14ers. Early August up there means strong high-elevation sun, real warmth in the open, and the very real chance of an afternoon mountain thunderstorm, so plan for sun, wind, and a fast weather change above treeline.

Do I need to worry about altitude at the Sheep Mountain Trail Runs?

Yes, more than almost any other factor here. With an average elevation over 10,600 feet, the thin air is the defining challenge of this race, and runners coming from low elevation feel it the most. If you can, arrive several days early to start adjusting, or come in the day before and race before the worst of the altitude effect sets in, since partial acclimatization is tricky. Either way, pace the early miles conservatively, keep eating and drinking, and expect your normal climbing pace to feel harder than the grade alone would suggest.

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.