From the Organizer
The 40/50 Mile Challenge
The 40/50 Mile Challenge is a continuous loop endurance race designed for runners who want to push beyond traditional race formats while benefiting from a fully supported, centralized course.
Held alongside The Next Loop Endurance Series, this event runs on the same 3.1-mile (5K) loop, but unlike the hourly format, competitors in the 40/50 Mile Challenge run continuously with a strict time cutoff.
This format offers a true ultra-distance experience—simplified logistics, consistent footing, and constant access to aid and support.
Event Format
Distances: 40 Miles or 50 Miles
Loop Length: 3.1 miles (5K)
Course Type: Continuous loop trail race
Time Limit: 12 hours
Start/Finish: Same location each loop
Aid Station: Fully stocked at every lap
Staging Area: Designated personal staging area near start/finish
Runners complete repeated loops until they reach their chosen distance or the time limit expires.
Who Should Run the 40/50 Mile Challenge
This event is ideal for:
Runners attempting their first ultra distance
Athletes stepping up from a marathon or 50K
Experienced ultrarunners seeking a fast, efficient course
Competitors who value logistics simplicity and strong support
The loop format removes navigation concerns and allows athletes to focus entirely on pacing, fueling, and mental toughness.
Events
Weather
It's too far out for a forecast, so here's what weather on this date is normally like in the area. A race day forecast will replace this as race week approaches.
Typical High
79°
Typical Low
59°
Chance of Rain
31%
Based on US Climate Normals data from Mundelein 4 Wsw, 6 mi from the venue.
Host City
Population
26,772
as of 2023
City Elevation
706 ft
Nearest Airport
ORD
Chicago O'Hare International Airport · 18 mi
Time Zone
Central Time
From Endurance Grid
A mid-size host city. Enough lodging and amenities to keep race weekend easy, without big-city sprawl.
Race Location
Your Next Start Line
Every finish line starts with a single decision. Claim your spot at The Next Loop 40M/50M Challenge | Half Day Forest Preserve, put it on the calendar, and turn “someday” into a start date.
73
Days to train
Coming Up
Stars and Stripes - America's 250th Anniversary Challenge
5 miles away
The Police Chase Twilight 5k @ Vernon Hills Days
1 mile away
Alpine Races 5k and 10 Mile
5 miles away
Healthy Kids Running Series Fall 2026 - Libertyville, IL
4 miles away
From Endurance Grid
This race spans more than one sport — here’s a guide to each, so you can understand what’s involved and decide if it’s the right fit. For course distances, logistics, and race-day specifics, always defer to the race organizer’s event page.
From 5K to marathon, running races are the most accessible entry point into endurance sport. There's a distance for every fitness level and a community at every start line.
Anything beyond the marathon — 50K, 50-mile, 100K, 100-mile, and timed events. Aid stations, cutoffs, and finishing as the goal.
Frequently Asked Questions (FAQs)
The Next Loop 40M/50M Challenge | Half Day Forest Preserve
Aug 29, 2026