Mamba 100 - Memphis, TN
Memphis, United States • 7-8 Nov 2025
Event overview
The Mamba 100 takes place November 7-8, 2025 at the Wolf River Refuge Trailhead on S. Walnut Bend Rd., Memphis, TN. The event offers these distances:
- 100 Miler
- 100K
- 50K
- 25K
The course is organized as a loop of about 14 miles along the Wolf River with mostly single-track trail and low elevation gain. Distances are completed by repeating loops: the 100 miler is seven loops, the 100k is four loops plus a shorter starter loop, the 50k is two loops, and the 25k is one loop.
Logistics and rules
There are two staffed aid stations: the Start/Finish at the Wolf River Refuge Trailhead and the Walnut Grove Bridge (passed twice per loop). Aid stations are stocked with water, electrolyte drink, soda, and standard ultra fare. Drop bags are allowed only at the Start/Finish aid station. Packet pickup is at the Start/Finish location on the day before the race.
Pacers are permitted for the 100 miler and 100k only; one pacer at a time, starting from the Start/Finish area, with specific loop eligibility for when pacers may join. Runners must carry their own gear - no muling - and crew access is limited to the Start/Finish area. General rules include no course cutting, no stashing supplies on course, and respect for volunteers and other users; receiving certain medical treatments ends a runner’s race. Age minimums: 100 Miler and 100K 18+, 50K 16+ with guardian waiver, 25K 13+ with guardian waiver. The 100 miler is a Western States qualifying race. Awards are given to the top three men and women in each distance. Visit the organization's website for the most recent information.