The Mammoth Trail Run
The Mammoth Trail Run puts a 100K and 50K on steep, rocky ranch trails near Glen Rose, Texas, with a 26 hour cutoff that runs deep into the night.
Every link above goes to the race, its timing provider, or an official registration partner. Last checked July 25, 2026.
Quick facts
- 100K flagship with a 26 hour cutoff, so overnight running is normal for much of the field.
- Steep, rocky ranch terrain that rewards aggressive trail shoes.
- 50K, 25K, 10K, 5K, and a kids dash share the ranch on race day.
- Primitive camping at High Hope Ranch shortens race morning logistics.
2026 The Mammoth Trail Run registration
Registration for the 2026 The Mammoth Trail Run runs through the official registration page at runsignup.com.
About the The Mammoth Trail Run
High Hope Ranch covers roughly 1,000 acres of rugged terrain southwest of Fort Worth, and The Mammoth turns it into a full trail race day, from a 1K kids dash up to a 100K ultra. Primitive camping on the ranch keeps race morning simple, and the whole event stays contained on private land rather than spread across public roads.
Course
The ranch trails are steeper than most runners expect from this part of Texas, with sharp punchy climbs and descents on loose, rocky footing. Organizers push trail shoes with real traction for a reason. The 100K starts at 7:00 AM and carries a 26 hour cutoff, so most of that field runs through the night, and the race is cupless, so carried bottles or flasks are required.
Race-day weather
Early October in North Texas often starts in the 60s and can push into the 80s by afternoon, with humidity that makes the exposed sections feel hotter. The 100K field gets relief overnight, then faces a second warm stretch the next morning.
Past The Mammoth Trail Run dates and results
| Year | Date | Status | Results |
|---|---|---|---|
| 2026 | Saturday, October 10, 2026 | Upcoming | — |
The Mammoth Trail Run FAQ
When is the The Mammoth Trail Run?
The 2026 The Mammoth Trail Run is on Saturday, October 10, 2026.
How do I register for the The Mammoth Trail Run?
Register for the The Mammoth Trail Run through the official registration link: marathonscout.com/go/the-mammoth-trail-run/register. It opens the race registration page at runsignup.com.
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