40/50 Mile Challenge, Lake Carl Blackwell

The Lake Carl Blackwell 50 Mile Challenge is a gritty, no-nonsense test of pacing and patience on a scenic 3.1-mile (5K) loop trail in Stillwate, OK at Lake Carl Blackwell Park.

This is a continuous 50-mile trail race run alongside The Next Loop Endurance Series. Same fully stocked Start/Finish aid station every lap. Easy fueling. Simple logistics. All the support, every time through.

You’ll knock out 16 loops to hit 50 miles (trail measurements may vary slightly). A 12-hour cutoff keeps things moving and rewards smart pacing, with steady energy and a strong community vibe all day long.

You can stage gear at your vehicle or in the designated staging area. Pacers are welcome after 4:00 PM.

Chasing a PR? Eyeing your first 50-miler? Just looking for a long, honest day on trail? The Next Loop 50 Mile Challenge delivers the full ultra experience, one loop at a time.

Upcoming Races

Nov 21 2026
40 Miles
The 40/50 Mile Challenge at Lake Carl Blackwell is a continuous loop trail ultra held on the scenic Shredder’s Gulch 3.1-mile loop, featuring runnable lakeside terrain with gentle rolling elevation, dirt trails, grassy sections, and open views typical of central Oklahoma trail systems. Runners complete repeated loops to reach either the 40-mile or 50-mile distance, both with a strict 12-hour cutoff. The loop format provides consistent footing and straightforward pacing while maintaining the feel of a true trail endurance event. A fully stocked aid station, personal staging area, and crew access are located at the start/finish and available every 3.1 miles, allowing easy fueling, gear changes, and logistical support throughout the race. Pacers are permitted after 2:00 PM. The course is designed to be approachable for first-time ultrarunners while still offering an engaging endurance challenge for experienced athletes seeking a well-supported, repeatable trail ultra environment.
Multiple Loop
12:00 Cutoff
2 Elevation Rating
Rolling, ~2500 feet in 50 miles
2 Surface Rating
Mostly groomed trail or dirt roads
Nov 21 2026
50 Miles
The 40/50 Mile Challenge at Lake Carl Blackwell is a continuous loop trail ultra held on the scenic Shredder’s Gulch 3.1-mile loop, featuring runnable lakeside terrain with gentle rolling elevation, dirt trails, grassy sections, and open views typical of central Oklahoma trail systems. Runners complete repeated loops to reach either the 40-mile or 50-mile distance, both with a strict 12-hour cutoff. The loop format provides consistent footing and straightforward pacing while maintaining the feel of a true trail endurance event. A fully stocked aid station, personal staging area, and crew access are located at the start/finish and available every 3.1 miles, allowing easy fueling, gear changes, and logistical support throughout the race. Pacers are permitted after 2:00 PM. The course is designed to be approachable for first-time ultrarunners while still offering an engaging endurance challenge for experienced athletes seeking a well-supported, repeatable trail ultra environment.
Multiple Loop
12:00 Cutoff
2 Elevation Rating
Rolling, ~2500 feet in 50 miles
2 Surface Rating
Mostly groomed trail or dirt roads

Results

50 Miles

Date Finishers Top Result (F) Top Result (M)
05/23/26 Results Not Available Submit Results

40 Miles

Date Finishers Top Result (F) Top Result (M)
05/23/26 Results Not Available Submit Results

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