Sawatch Ascent

A classic, high-alpine, vert-heavy Colorado 50k! Get some miles on the Colorado Trail and run all the way to 13,150' feet in elevation! Starting and finishing at the base of Mount Princeton, runners are treated to panoramic views of the Sawatch Range and the gorgeous Arkansas River Valley. The race runs in a large lollipop and is essentially one long 7000' foot climb and one long 7000' descent. The beginning and end have a mix of dirt and paved roads, but the middle is 25 miles of uninterrupted singletrack, including 12 miles on the Colorado Trail. Yet, despite the amount of vert this course is surprisingly runnable, especially for a runner with mountain experience. Add in the changing aspen leaves and the (usually) perfect fall weather and you've got yourself one hell of end-of-the-season race. As an added bonus, the course shares some similarities with the High Lonesome 100 course and is put on by the same folks at Freestone Endurance.

The race starts on Sunday, September 28th, 2025 at 7:30am and runners have 11 hours to complete the course. There are three aid stations (not counting the Start/Finish) that are fully stoked with the typical aid station fare as well some tasty treats to surprise you and water and Tailwind are available at all aid stations. Runners can camp at the start/finish line for $15/night and space is limited to 35 spots. The race is capped at 250 runners Runners get a finishers medal, race shirt, free full resolution professional images, and free drinks (alcoholic and non) at the finish line. If you don't want a shirt and/or medal, you can select that during registration to save $10-20. 

As an added challenge, runners can attempt the Sawatch 50/50 by registering for the West Line Winder 50k on the same weekend! Finishers of the Sawatch 50/50 will get a special award and place awards for the top 3 overall men and women.

Cancellation, Deferral, and refund Policy: Runners can defer 50% of their entry to the following year so long as they request it by September 1st. We do not offer refunds, but you may purchase third-party insurance during registration which may allow you a refund. Please see the website for the full details. 

Key details:

• When: Sunday September 28th, 2025 at 7:30am
• Where: Nathrop, Colorado (coordinates: 38.74275, -106.15964)
• Course: 33 miles, 7000' of vert, 8200' low point to 13,150' high point, average elevation 9800'
• Trail type: 26 miles of singletrack, 4.5 miles of pavement, 2.5 miles of gravel roads
• Cutoff: 11 hours
• Extra challenge: Sawatch 50/50!

Ready to test your limits? The Sawatch Ascent brings a highly anticipated Ultra to Nathrop on September 27, 2026. Expect a fantastic route right in the heart of Colorado.