⏵ Course guide · Colorado high-altitude flagship
The Human Potential Running Series' Silverheels Trail Runs sits near Como, Colorado, at an average elevation over 10,000 feet, beneath the "Decalibron" 14ers, with distances from 10 miles up to a full 100 miler. I will walk you through the terrain and distance menu first, then give you a pacing and fueling plan built for sustained high-altitude effort. There are free calculators along the way to dial in your own numbers.
The next edition's date is not yet officially confirmed by HPRS at time of writing; the July 2027 window comes from race aggregators, not the organizer directly. Confirm the current date and details on RunSignup or HPRS's own site before you commit.
Silverheels runs at an average elevation over 10,000 feet, in what HPRS calls one of the most visually stunning areas of Colorado, a mix of singletrack, fire roads, and dirt road through South Park.
The longer distances take runners through old ghost towns and past abandoned mines, beneath the watchful presence of Silverheels Mountain herself, with sweeping views of the South Park Valley and the towering Decalibron 14ers. For runners out overnight on the 100K or 100 Mile, expect genuinely dark, high-altitude skies.
The 10-Mile and 19-Mile options run the Gold Dust Trail, a different flavor of the same high country: massive aspen groves, numerous high mountain creek crossings, old mining encampments, and a miners ditch hand-dug in the late 1800s. It is a more contained taste of Silverheels' terrain for runners not ready for the full ultra distances.
An average course elevation over 10,000 feet is the single biggest factor in your pacing here, well before terrain or distance enters the conversation.
A grade-adjusted pace target built specifically for this elevation gives you a far more honest number than any pace you have run at lower altitude. Even flat or gently rolling sections will cost more here than the grade alone suggests, since sustained effort above 10,000 feet taxes you differently than a short climb does.
On the 60K, 100K, or 100 Mile, a vert-aware finish prediction built off your early splits at this altitude is far more useful than any flat-course time you might bring in from lower elevation. Check it against your goal early, while you still have room to adjust effort rather than expectations.
⏵ Free tools to pace this course
Altitude above 10,000 feet suppresses appetite for a lot of runners right when calorie demand is at its highest, so plan around that ahead of time.
Aim for roughly 60 to 90 grams of carbohydrate per hour on the longer distances, and test whatever gels, chews, or real food you plan to use at elevation beforehand. What sits fine at sea level does not always sit fine above 10,000 feet.
Sodium in the 300 to 700 mg per liter range covers most runners. South Park mornings can be genuinely cold even in July, while midday sun at this elevation is intense, so plan your hydration and clothing for both extremes across a long day.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and terrain above 10,000 feet 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, whichever Silverheels distance you're targeting, and your projected splits above 10,000 feet. Summit Line reads your real training, builds a plan for sustained high-altitude effort, and rehearses your fueling so race day is something you execute, not guess at.
The most recent confirmed edition ran July 10-11, 2026, and sold out. Race aggregators list a next date around July 9-10, 2027, but that date carries a "to be announced" status on the aggregator data we could check, meaning the Human Potential Running Series has not published an official confirmed date on a source we could directly verify. Check HPRS's own site or RunSignup listing for the confirmed date before making travel plans.
Very. This is a high-altitude race with an average course elevation over 10,000 feet, one of the highest race venues in Colorado, running through high alpine and sub-alpine meadows beneath the "Decalibron" 14ers. Whichever distance you choose, from the 10-mile up to the full 100 miler, altitude alone will slow you well below what the same terrain would demand at lower elevation.
The event spans a full range: 10 Mile, 19 Mile, 50 Mile, 60K, 100K, and the flagship 100 Mile. The 10 and 19-mile options run the Gold Dust Trail through massive aspen groves, high mountain creeks, old mining encampments, and a hand-dug miners ditch from the late 1800s, while the longer distances add more of the high alpine terrain around Silverheels Mountain and the South Park Valley.
Racing consistently above 10,000 feet changes fueling in ways lower-elevation ultras do not: altitude suppresses appetite and can slow gut absorption, even as your body burns through carbohydrate faster. Aim for roughly 60 to 90 grams of carbohydrate per hour on the longer distances, leaning on easily digestible options if altitude blunts your appetite, and sodium in the 300 to 700 mg per liter range. Colorado high country can also swing from cold mountain mornings to strong midday sun, so plan your hydration for both. Build your numbers with the free ultra fueling calculator before race day.
Demand is real: the 2026 edition sold out completely and closed its wait list before race day, even after absorbing extra entries from runners affected by the cancellation of nearby Ouray 100 and Silver Rush/Leadville events that year. If you want in on a future edition, register as early as entries open rather than waiting.
Not as a starting point. An average course elevation above 10,000 feet is a serious test even for experienced mountain ultrarunners, and the 100 Mile distance compounds that altitude fatigue over a full day or more on course. If you are newer to altitude or to the 100-mile distance, consider one of Silverheels' shorter options first, the 10, 19, or 50 mile, to learn how your body handles this elevation before committing to the full 100.
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<a href="https://runsummitline.com/guides/silverheels-100">The Silverheels Trail Runs course guide</a>This guide is independent and for planning only. The next edition's date is an estimate from race aggregators, not an HPRS-confirmed date, and the course details, distances, and terrain come from public sources that can change year to year. Confirm the current date and specifics with the official race before you register or run. The fueling and pacing advice is general and not medical advice.