Ultramarathon

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.

Next raceSaturday, October 10, 2026
Distance categoryUltramarathon
LocationGlen Rose, Texas
Get alertsLast checked August 4, 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.

About 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 Mammoth Trail Run dates and results

YearDateStatusResults
2026Saturday, October 10, 2026Upcoming

The Mammoth Trail Run FAQ

When is The Mammoth Trail Run?

The 2026 Mammoth Trail Run is on Saturday, October 10, 2026.

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