⏵ Course guide · Flat and fast, Lake County
The Des Plaines River Trail Races send Half Marathon, Marathon, 50K, and 50 Mile fields out from Half Day Forest Preserve onto flat, crushed-gravel trail through Lake County forests and wetlands, a course built for personal bests and Boston-Qualifying times, not technical terrain. I will walk you through the course first, then give you a pacing and fueling plan built for a fast, flat ultra, plus free tools to dial in your own numbers.
These facts come from the official race site. Check the current year details, cutoffs, and aid stations before you commit. Race logistics change year to year.
All four distances run on the Des Plaines River Trail out of Half Day Forest Preserve, on a wide, crushed-gravel surface free of roots and rocks, alternating between lush forest and open wetland with vivid October color changes along the way.
With expected cool temperatures, flat terrain, and an ideal running surface, this course is designed to run fast. All major road crossings are handled by bridges or viaducts, leaving only a small number of minor crossings depending on distance: 4 on the 50K/50 Mile, 2 on the Marathon, and none at all on the Half Marathon.
The race runs the second weekend of October every year, hosted by Ornery Mule Racing along the Des Plaines River Trail in Lake County. Current Race Director Michele Hartwig has been part of the race as both volunteer and finisher before taking over direction, continuing a course originally designed and built by earlier organizers.
The Marathon distance here is a Boston Qualifier, a rare pairing of trail scenery with a legitimately fast, flat certified-feeling course. If chasing a BQ time on dirt rather than pavement appeals to you, this is one of the more direct routes to try it.
Without significant climbing or technical footing to slow you down, pacing here is closer to a road ultra than a mountain race: the main risk is starting too fast simply because the surface makes it feel easy.
On a course this flat, a straightforward pace target based on your fitness and goal time matters more than grade adjustment. Set a realistic per-mile pace for the 50K or 50 Mile and hold it, resisting the temptation to bank early miles just because the crushed gravel invites a fast start.
A finish prediction built from your training gives you real mile-by-mile timing to plan aid and fueling stops around, especially useful on a fast, flat course where the difference between an even effort and a positive split can be significant over 50 miles.
⏵ Free tools to pace this course
Expected cool temperatures and a flat, even surface make this a course where consistent, planned fueling pays off, since there is little terrain-driven variation in effort to disrupt your intake schedule.
Aim for roughly 60 to 90 grams of carbohydrate per hour on the 50K and 50 Mile. Because the surface stays consistent, this is a good course to practice metronomic, scheduled fueling rather than reacting to changing terrain.
Sodium in the 300 to 700 mg per liter range covers most runners given the expected cool temperatures. Even on a cool day, a long 50 Mile effort still adds up, so do not assume the mild weather means you can skip planning sodium intake.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and a cool October Lake County day 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 this exact flat, fast Des Plaines River Trail profile. Summit Line reads your real training, builds a plan for chasing a PR or a Boston Qualifier, and rehearses your fueling so race day is something you execute, not guess at.
This is one of the flattest, fastest 50 milers on the Midwest calendar. The course runs on wide, crushed-gravel trail through alternating forest and open wetland with no roots or rocks to navigate, and only 4 minor road crossings across the entire 50K/50 Mile route, all otherwise bridged or routed through viaducts. The challenge here is almost entirely about managing a long day on your feet and your fueling, not technical terrain or big climbs.
The official race site describes the Des Plaines River Trail as very flat, and no elevation gain figure is published for any distance. This is a course built for speed rather than vertical, which is why the Marathon distance is set up as a Boston Qualifier.
Mid-October in Lake County usually brings cool temperatures, which the race itself notes is part of what makes the trail run fast. Aim for roughly 60 to 90 grams of carbohydrate per hour on the 50K and 50 Mile, and sodium in the 300 to 700 mg per liter range. Because the surface is flat and fast, many runners can hold a more even effort here than on a technical course, so build a fueling plan around steady, predictable intake rather than one that reacts to big terrain changes. Build your numbers with the free ultra fueling calculator before race day.
Yes. The race site states directly that the Marathon distance is a Boston Qualifier, run on the same flat, crushed-gravel Des Plaines River Trail as the ultra distances, with expected cool temperatures and only 2 road crossings on the marathon course.
The course runs on the Des Plaines River Trail in Lake County, a flat, wide, crushed-gravel path free of roots and rocks, alternating between lush forest and open wetland. Major road crossings are handled by bridges or viaducts, leaving only a handful of minor crossings depending on distance: 4 for the 50K/50 Mile, 2 for the Marathon, and none for the Half Marathon.
The 50K here is one of the more approachable first-ultra options around: flat, wide, well-maintained crushed gravel with minimal technical demands and very few road crossings to navigate. If your goal is to focus purely on distance and fueling without also learning technical trail skills, this is a strong choice for a first 50K or even a first 50 Mile.
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<a href="https://runsummitline.com/guides/des-plaines-river-trail-races">The Des Plaines River Trail Races course guide</a>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.