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