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 friendly, low-key atmosphere appreciated by both racers and their crews. As a late-season event, snow is common, and recent safety improvements aim to ensure the race continues despite adverse weather, prioritizing runner and volunteer safety. Visit the organization's website for the most recent information.