Colorado Ultramarathons

49 upcoming ultras across Colorado, updated nightly. Want radius search and maps? Open these in the Race Finder.

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When to race: ultras in Colorado

Colorado has 49 upcoming ultras over the next 12 months. Among complete calendar months, July 2027 has the most listed races, with 8. Most are around Colorado Springs, Estes Park, Crested Butte. The next one is Mountain Peacock 50k on November 15 in Golden.

November 2026

December 2026

January 2027

February 2027

March 2027

April 2027

May 2027

June 2027

July 2027

August 2027

September 2027

October 2027

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More Colorado: Marathons · Half Marathons · 5K Races · 10K Races · All Colorado races · Browse by state