The Mammoth at Dinosaur Valley
Glen Rose, United States • 10-11 Oct 2026
Event overview
The Mammoth - Glen Rose, TX takes place on Saturday October 10 to Sunday October 11, 2026 at High Hope Ranch and Retreat Center in Glen Rose, TX 76043. The event offers multiple trail distances and a separate fun run for children.
Distances:
- 100K
- 50K
- 25K
- 10K
- 5K
- Mighty Mammoth 1K Fun Run (non-chip timed)
Course and logistics
The course uses two loop sections: a 3.5-mile loop and a 7-mile loop. Both loops combined form a 10.5-mile lap. The starting line and main race hub are at the ranch main lodge. There are two aid stations on course—the main lodge and Matazamo ranch house—located about 3.5 miles apart. The 100K event has a 26-hour cut-off time. A pacer registration option is available for those pacing 100K athletes.
All participants receive an official race shirt and a finisher medal; 100K finishers receive finisher buckles. There are no place awards. Packet pickup is on race day at the site. Parking is included in the price. Overnight camping is available for a separate fee of $10 per person, maximum six people per site, payable at the gate; sites are boondocking only, no hook-ups. Pets are not allowed. The event encourages attendees to bring their own bottles. Refunds are non-refundable, but transfers to another person, category, or Mammoth event are allowed. Visit the organization's website for the most recent information.