4 aidUltramarathons in Colorado
As of October 6, 2026, Crewable lists 30 upcoming ultramarathons in Colorado from October 2026 to September 2027. The next is Rocky's Backyard Ultra on October 10 in Estes Park. Registration is open for 9. 2 advertise prize money.
Sources: UltraSignup, RunSignUp, UTMB, race organizers and race websites
With aid station data
4 aid
13 aidin 11 days
Blue Sky Trail Marathon & Half Marathon
Fort Collins, CO3,500 ft gain
MarathonHalf Marathon
Open until Oct 17from $110
6 aid7 aid
1 aidRace calendar
October 2026
8 racesBlue Sky Trail Marathon & Half Marathon
Fort Collins, CO3,500 ft gainMarathonHalf MarathonOpen until Oct 17from $110
November 2026
6 racesDecember 2026
2 racesApril 2027
3 racesMay 2027
4 racesJuly 2027
2 racesAugust 2027
3 racesSeptember 2027
2 racesQuick answers
What is the next ultramarathon in Colorado?
Rocky's Backyard Ultra, on Saturday, October 10, 2026, in Estes Park. Distances: Backyard Ultra.
How many ultramarathons in Colorado have open registration?
9 of the 30 list registration as open as of October 6, 2026, including Suffer Better 10th Annual Fall Trail Runs, Blue Sky Trail Marathon & Half Marathon and Bobcat Trail Races.
Which ultramarathons in Colorado offer prize money?
2 races advertise prize money, including Rocky's Backyard Ultra ($1,000).
What is the busiest month for ultramarathons in Colorado?
October 2026, with 8 of the 30. November 2026 follows with 6.
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