⏵ Course guide · Rocky Mountains summer trail race
The Human Potential Running Series' Summits Trail Runs spans Granby Ranch Resort in Colorado's Rocky Mountains, from a 6-Mile shakeout up to a full 55K or the 14-Hour Elevation Challenge, all sharing singletrack, alpine meadows, and aspen groves. I will walk you through the terrain and distance menu first, then give you a pacing and fueling plan built for mountain elevation. There are free calculators along the way to dial in your own numbers.
These facts come from the official Human Potential Running Series registration listing. Check the current year details before you commit. Race logistics change year to year.
Summits runs entirely on Granby Ranch Resort property, mixing singletrack trail with alpine meadows, dense aspen groves, and stretches of rugged alpine terrain, all under sweeping Rocky Mountain views.
From the 6-Mile up through the Half Marathon, Marathon, 55K, and the 14-Hour Elevation Challenge, every distance draws from the same resort trail network. That means you can scale your ambition to your current fitness while still experiencing the same singletrack and alpine scenery as the ultra runners.
HPRS describes the routes as twisting through varying elevation gains that test endurance as much as raw mileage. Expect the terrain itself, not just the distance on your bib, to be the primary challenge here.
With every distance sharing the same generous 6:00 AM to 8:00 PM window, the pressure here is less about beating a cutoff and more about pacing a genuinely mountainous course well.
A grade-adjusted pace target built for Granby Ranch Resort's alpine terrain gives you an honest number for what is sustainable across singletrack, meadow, and forest sections that will vary in footing and grade throughout the course. With the shared 14-hour window, there is little reason to rush the early miles.
A vert-aware finish prediction built off your early splits tells you honestly whether your pace is sustainable for the full 55K or a strong Elevation Challenge result, while you still have time to adjust rather than react.
⏵ Free tools to pace this course
A 14-hour window at Granby Ranch Resort in June covers real temperature swings, from a cool 6:00 AM start to a warm afternoon on exposed alpine terrain.
Aim for roughly 45 to 75 grams of carbohydrate per hour on the Marathon or 55K, scaling up toward 60 to 90 if you're pushing hard for distance in the Elevation Challenge. The shorter distances can run a lighter, simpler fueling plan given their shorter time on course.
Sodium in the 300 to 700 mg per liter range covers most runners, leaning higher as the day warms and you move into more exposed alpine sections. Mountain sun at elevation is stronger than it feels.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and a June day in Colorado's Rocky Mountains 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 Summits distance you're targeting, and your projected splits on Granby Ranch Resort's alpine terrain. Summit Line reads your real training, builds a plan for mountain climbing, and rehearses your fueling so race day is something you execute, not guess at.
It is a 14-hour timed format that shares the same 6:00 AM to 8:00 PM window as every other distance at the event. Rather than a fixed course, you run as much of Granby Ranch Resort's trail network as you can within the 14 hours, and your result is your total distance covered.
Alongside the 14-Hour Elevation Challenge, HPRS runs a fixed 55K, Marathon, Half Marathon, and 6-Mile, all within the same 6:00 AM to 8:00 PM race window at Granby Ranch Resort. That range makes it accessible for a shorter mountain outing or a full day-long ultra effort at the same event.
A June date at Granby Ranch Resort in Colorado's Rocky Mountains typically means cool mornings warming into a sunny, potentially hot mid-day, all at real mountain elevation. Aim for roughly 45 to 75 grams of carbohydrate per hour for the Marathon or 55K, and sodium in the 300 to 700 mg per liter range, leaning higher if the afternoon runs warm. Because the 14-hour window covers a full day of changing conditions, plan your fueling to shift as the temperature does. Build your numbers with the free ultra fueling calculator before race day.
Every distance at Summits, from the 6-Mile up through the 55K and the 14-Hour Elevation Challenge, shares the same overall 6:00 AM to 8:00 PM race window. That gives shorter-distance runners a very generous cushion and gives 55K and Marathon runners a full 14 hours to work with on genuinely mountainous terrain.
Expect singletrack trails winding through alpine meadows, aspen groves, and dense forest, with stretches of rugged alpine terrain and sweeping Rocky Mountain vistas throughout. HPRS describes the event as testing endurance through varying elevation gains as the routes twist across the resort property.
The distance range makes it a flexible entry point: the 6-Mile or Half Marathon let you experience Granby Ranch Resort's terrain without committing to a full ultra, while the shared 14-hour window across all distances means even the 55K carries a generous cushion for a first-time mountain ultra runner learning to manage altitude and terrain together.
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<a href="https://runsummitline.com/guides/summits-trail-runs">The Summits Trail Runs course guide</a>This guide is independent and for planning only. The course details, dates, and event menu 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.