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⏵ Course guide · Colorado ultra

The Bear Chase Course Guide

The Bear Chase is the Front Range’s big, friendly ultra festival, a 100K, 50 Mile, and 50K run on a fast, mostly non-technical 12.5-mile loop at Bear Creek Lake Park just outside Denver. It is a classic first ultra, but the loop format, the altitude, and the October sun all change how you should run it. I will walk you through the course first, then give you a pacing and fueling plan built around the laps and the cutoffs. There are free calculators along the way to dial in your own numbers.

⏵ At a glance

The Bear Chase quick facts

Date
Saturday, October 3, 2026 (ultras); shorter races Sunday, October 4
Location
Bear Creek Lake Park, Lakewood, Colorado (Denver Front Range)
Distances
100K, 50 Mile, and 50K (plus a Sunday half marathon, 10K, and 5K)
Elevation gain
100K: about 4,250 ft · 50M: about 3,400 ft · 50K: about 1,930 ft
Ultra starts
100K 5:30 AM · 50 Mile 6:30 AM · 50K 7:30 AM (Saturday)
Cutoff
Final lap must start by 6:00 PM (then hold under 16:45/mi to beat rolling aid-station cutoffs); 100K finish line closes 9:30 PM
Course
A 12.5-mile loop run multiple times, 95% dirt and singletrack, fast and non-technical
Qualifier
Not listed as a Western States, Hardrock, or UTMB qualifier

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

The course: where The Bear Chase is won and lost

Every distance here runs the same 12.5-mile loop at Bear Creek Lake Park, just a different number of times. The 50K is roughly two and a half loops, the 50 Mile about four, the 100K about five. The loop is about 95% dirt and singletrack, gently rolling, fast, and not technical, so this is one of the few ultras where you really can run most of the course if your legs hold up.

The loop: runnable, repeatable, and a head game

There is no signature climb on this course and nothing technical to scare you. Each loop carries roughly 850 feet of gain spread across rolling terrain, so the climbs are short and the descents are cruisey. That sounds easy, and physically it is gentler than most mountain ultras. The catch is the repetition: you pass the same start/finish, the same lake, the same trail junctions every loop, and the race becomes as much a mental grind as a physical one.

Use that to your advantage. Break the day into laps instead of miles, give each loop a job (settle in, hold steady, grind, hang on, finish), and let the familiar landmarks tell you how you are trending. The runners who fall apart here usually do it in their heads on loop three or four, not because the trail beat them up.

Altitude and the October sun

The real difficulty at The Bear Chase is not the dirt, it is the air and the sky. Lakewood sits near 5,600 feet, so if you are coming from sea level the altitude will quietly tax you all day, especially on the climbs and especially late. And early October on the Front Range is a coin flip: you can get a cold or even snowy dawn and then a warm, fully exposed afternoon with very little shade out on the loop.

Respect both. Ease your effort a notch if you live low, and plan your layers and your sun protection for a big temperature swing across the day. The looped course makes this manageable because you come back to your start/finish gear every lap.

The looped format is a gift for crew and drop bags

Because you return to the same start/finish area every 12.5 miles, The Bear Chase is one of the easiest ultras to crew and to stock with a drop bag. Your people see you every loop, you can stage exactly the food and gear you want, and there is no logistics puzzle of leapfrogging remote aid stations down a point-to-point course.

Plan for it. Lay out your loop-by-loop nutrition, a swap of socks or a headlamp for the late laps, and anything you want for the swing from cold morning to hot afternoon. Aid stations sit around the loop too (start/finish plus stops like Homestead and Cattail Creek), with water, Tailwind, soda, and real food like PB&J and fruit, so you are never far from a refill.

Pacing strategy for a fast, looped ultra

Because the course is so runnable, the temptation is to run it too fast early. With modest, rolling vert and a long day ahead, The Bear Chase rewards even effort and lap discipline over hero pacing on loop one.

Run by effort, not by how easy loop one feels

The classic mistake on a non-technical course like this is banking time early because the trail lets you. Do not. Hold a steady, conversational effort that accounts for the altitude and the rolling climbs, and let the flat, runnable sections come to you instead of forcing them. A grade-adjusted pace helps you turn your real fitness into honest targets for the little climbs and descents so you are not red-lining on loop one and shuffling on loop four.

Build a finish prediction, then back it into the cutoffs

Do not guess your Bear Chase finish off a flat road time. The altitude, the cumulative vert, and the heat all add real minutes over a long day. A vert-aware finish prediction gives you a realistic window for your distance, and on a looped course you can do something most races will not let you: turn that into a per-lap target and check it against the 6:00 PM final-lap cutoff and the 9:30 PM finish every single time you come through the start/finish.

⏵ Free tools to pace this course

Fueling strategy for the duration and the altitude

Whether you are out for five hours on the 50K or pushing toward the 9:30 PM cutoff on the 100K, this is a long day where carbohydrate, sodium, and fluid matter as much as fitness. The looped course makes a precise plan easy to execute.

Carbs: steady, trained, and lap by lap

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 altitude and the afternoon sun can dull your appetite and slow your stomach, so keep intake steady and easy to swallow rather than gambling on big late doses. The advantage here is the loop: stage exactly what you want at your start/finish drop bag and refresh it every 12.5 miles, so you never coast a lap on whatever happens to be at an aid table. Practice your real race-day carb rate on long runs so 80-plus grams an hour feels normal.

Sodium and fluid: plan for the dry air and the sun

Colorado air is dry and the midday sun out on the exposed loop is no joke, so do not undersalt. Many runners land around 400 to 700 milligrams of sodium per liter of fluid, and more if you are a heavy or salty sweater. Drink to thirst between aid stations, then top off every time you come through, since on a looped course there is no reason to ration to empty. Weigh yourself before and after a long run to find your real sweat rate, then build the plan around your own number instead of a generic chart.

⏵ Build your fueling plan

Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and your Bear Chase distance 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, your Bear Chase distance, and your projected lap splits. Summit Line reads your real training, builds a plan for the duration and the altitude, and rehearses your fueling so race day is something you execute, not guess at.

Start free →Explore the demo

The Bear Chase FAQ

How hard is The Bear Chase?

The Bear Chase is one of the friendlier ways to run a long ultra, but long is still long. The course is a 12.5-mile loop at Bear Creek Lake Park, about 95% dirt and singletrack, fast and non-technical by trail standards, with modest climbing (roughly 4,250 ft for the 100K, 3,400 ft for the 50 Mile, and 1,930 ft for the 50K). There is no monster climb and no real technical danger, so the difficulty is about repetition, the Front Range sun, and the altitude rather than the terrain. The generous cutoffs (final lap out by 6:00 PM, 100K finish by 9:30 PM) give a prepared runner real room to walk a lot and still finish.

How much climbing is in The Bear Chase?

It depends on your distance because each one is the same 12.5-mile loop repeated. The 100K stacks up about 4,250 feet of total gain, the 50 Mile about 3,400 feet, and the 50K about 1,930 feet, per the race. That works out to roughly 850 feet of climbing per loop, spread across rolling, runnable terrain rather than one big sustained ascent. Confirm the current numbers on the official site, since the exact course can shift slightly year to year.

What are the cutoff times for The Bear Chase?

The big one to know is the final-lap cutoff: you have to leave the start/finish on your last loop by 6:00 PM, and from there you need to hold a pace faster than about 16:45 per mile to stay ahead of the rolling cutoffs at each aid station. The 100K finish line closes at 9:30 PM. Because it is a looped course, you get checked against the clock every time you come through the start/finish, so you always know where you stand. Always verify the current cutoffs in the race-day details before you start.

What is the loop and aid-station setup at The Bear Chase?

The whole race is built on a single 12.5-mile loop at Bear Creek Lake Park that you run multiple times depending on your distance (the 50K is roughly two and a half loops, the 50 Mile about four, the 100K about five). Aid stations sit around the loop (start/finish plus stops like Homestead and Cattail Creek), so you are never far from water, Tailwind, soda, and real food like PB&J and fruit. The looped format is a gift for crew and for drop bags, because you return to the same start/finish area every lap. Confirm the current aid layout and what each station stocks before race day.

What is the terrain and weather like at The Bear Chase?

The footing is easy by ultra standards: about 95% dirt and singletrack, gently rolling, fast, and not technical, so you can actually run most of it. The real variables are sun and altitude. Lakewood sits near 5,600 feet, and early October on the Front Range can swing from a warm, exposed, sunny afternoon into a cold or even snowy morning. Plan for a chilly dark start, real midday sun with little shade, and a temperature swing across the day.

Is The Bear Chase a good first ultra?

Yes, it is one of the better places in Colorado to run a first 50K, 50 Mile, or even 100K. The non-technical loop, the frequent aid, the easy crew access, and the forgiving cutoffs all stack in a first-timer’s favor, which is exactly why Aravaipa pitches it that way. The honest caveats are the altitude if you are coming from sea level and the monotony of repeating a loop, so train your legs for time on feet and rehearse your fueling. Get those two right and the course gives most committed runners a real shot at the finish.

This guide is independent and for planning only. The course details, dates, start times, 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.