Rio Grande 100

South Fork, United States • 23 Aug 2025

The Rio Grande 100 is an ultramarathon held in South Fork, Colorado, starting and finishing along the Rio Grande River. The challenging 100-mile course traverses the La Garita Mountains, featuring diverse terrain from arid forests to alpine tundra, with runners crossing elevations above 12,000 feet four times. Participants experience scenic trails adorned with golden aspen leaves and rugged rocky sections. Known for its demanding Rocky Mountain conditions, the race maintains a low-key, friendly atmosphere appreciated by both racers and their crews. As a late-season event, it often faces snow, prompting enhanced safety measures to ensure the race continues despite adverse weather, making it a rewarding and tough endurance challenge. Visit the organization's website for the most recent information.

Race information

100 mi
100 Miles
Visit the organization's website for the most recent information.
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