⏵ Course guide · Fort Collins timed ultra
Gnar Runners' Colorado 24 Hour Run puts you on a flat, USATF-certified one-mile dirt loop at Colorado Youth Outdoors near Fort Collins, and lets you choose how long you want to run it: 24 hours, 12 hours, or 6. I will walk you through the timed format first, then give you a pacing and fueling plan built for a flat loop instead of a mountain climb. There are free calculators along the way to dial in your own numbers.
These facts come from the official Gnar Runners race registration page. Check the current year details before you commit. Race logistics change year to year.
This is a timed event, not a fixed-distance race. You pick a division, 24, 12, or 6 hours, and your result is however many laps you complete in that window on the same 1.0002 mile dirt loop around Swift Ponds.
The loop has essentially zero net vertical gain or loss, small enough that mapping software cannot reliably measure it. That removes terrain from the equation almost entirely. What is left is pure pacing and fatigue management across however many hours you signed up for, which is exactly what a timed race is designed to test.
Runners flip direction on the loop every 6 hours, announced at the start/finish. If you are mid-loop when a reversal is called, finish that loop before turning around. It is a small rule with a real effect: it breaks up the monotony of running the identical direction for a full day, and it keeps the field mixing rather than settling into permanent packs.
The start/finish pavilion runs a full-service aid station on every lap, stocked with sports drink, gels, salty snacks, fruit, sweets, soda, hot soup and drinks, and hot sandwiches and burgers. Richardson Hall, the Colorado Youth Outdoors lodge, sits about 0.2 miles off the loop and stays open as a heated space to warm up, nap, or regroup, though you must return to the course at the exact point you left it. Runners can also set up a personal aid station in the designated lot across from the start/finish.
Without hills to force a slowdown, a timed race on a flat loop punishes an aggressive start more than almost any other ultra format. The temptation to bank early miles is real, and it is almost always a mistake.
Because the loop never changes, you get instant, honest feedback every single mile. Pick a per-lap pace you believe you can hold for 80 to 90 percent of your division length, and treat any lap that comes in meaningfully faster as a warning sign, not a victory. A race-time calculator built around your target duration gives you a lap-split number to check yourself against from mile one.
On a 12 or 24 hour effort, walking is not a failure mode, it is part of the plan. Deciding in advance how you will mix running and walking, by time, by lap count, or by feel, keeps you from making that decision for the first time at hour 14 when your legs have already made it for you.
⏵ Free tools to pace this event
Passing a full-service aid station every single mile is a luxury most ultras do not offer. Use that access to fuel steadily instead of gambling on big infrequent hits.
Aim for roughly 60 to 90 grams of carbohydrate per hour early on, then watch your gut. Long timed events, especially through an overnight 24-hour push, often force a shift toward real food, soup, and simpler carbs as the hours accumulate. The aid station's hot food and sandwiches exist for exactly that reason.
Sodium in the 300 to 700 mg per liter range covers most runners, and because the aid station is never more than a mile away, you can raise or lower your intake lap by lap based on how you actually feel rather than committing to one number for 24 hours.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal duration, and a long day and night on a flat loop 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 and your target distance, whether you are chasing 50 miles in 12 hours or a real 100-mile day. Summit Line reads your real training, builds a plan for sustained effort on a flat loop, and rehearses your fueling so race day is something you execute, not guess at.
It is a timed event, not a fixed-distance race. You choose a division, 24 hours, 12 hours, or 6 hours, and your result is simply how many miles you cover within that window on a flat, USATF-certified 1.0002 mile dirt loop at Colorado Youth Outdoors' Swift Ponds Campus near Fort Collins. You can start and stop as you choose, take breaks, nap, or just walk laps, as long as you cross the timing mat only on completed loops. The course opens at 8:00 AM Saturday and direction reverses on the loop every 6 hours.
Yes. The loop is essentially flat, with vertical gain and loss so small that mapping software struggles to register it above the margin of error. That makes this a very different kind of ultra than a mountain 24 hour race: your limiter here is almost entirely fatigue and pacing discipline, not terrain, since every lap of the 1.0002 mile course is the same flat dirt road.
A flat loop with a full-service aid station passed every single mile changes the fueling math compared to a remote mountain ultra. Aim for roughly 60 to 90 grams of carbohydrate per hour to start, and expect that number to drift lower as the hours pile up and your gut tolerance shifts, especially through the overnight stretch. Sodium in the 300 to 700 mg per liter range covers most runners, and you can adjust it lap by lap since the aid station is never more than a mile away. The Swift Ponds aid station stocks hot food, soup, sandwiches, and burgers alongside standard gels and sports drink, which matters a lot on an event this long. Build your starting numbers with the free ultra fueling calculator, then adjust by feel once you are out there.
There is no mileage cutoff in the usual sense. This is a timed event: the 24 Hour, 12 Hour, and 6 Hour divisions each simply end when their clock runs out, and your official distance is whatever you covered by that point. The only hard limits are the division time windows themselves, plus the mid-event direction reversal on the loop every 6 hours.
The entire course runs on dirt road around the Swift Ponds property, a 220-acre parcel with ponds, wildlife, and open Front Range views at roughly 4,826 ft elevation. There is no singletrack and no real climbing, so footing stays consistent lap after lap. The main variable across 24 hours is weather and daylight, not terrain, since November in northern Colorado can bring anything from mild sun to real cold overnight.
It is one of the more approachable entries into timed ultrarunning. The flat, short loop means you are never far from the aid station or your own drop zone, you can set up a personal aid area near the start/finish, and you get to choose your division, 6, 12, or 24 hours, based on what fits your training. Because your result is simply distance covered rather than a fixed course to complete, a first-timer can run conservatively and still walk away with a legitimate personal best in whatever direction they choose to measure it.
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<a href="https://runsummitline.com/guides/colorado-24-hour-run">The Colorado 24 Hour Run course guide</a>This guide is independent and for planning only. The course details, dates, 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.