4 aidTrail Races & Ultramarathons in Colorado
As of October 6, 2026, Crewable lists 44 upcoming trail races and 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 15. 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
1 aid
4 aid
7 aidRace calendar
October 2026
11 racesBlue Sky Trail Marathon & Half Marathon
Fort Collins, CO3,500 ft gainMarathonHalf MarathonOpen until Oct 17from $110
November 2026
11 racesDecember 2026
3 racesJanuary 2027
1 raceFebruary 2027
1 raceApril 2027
3 racesMay 2027
6 racesJuly 2027
3 racesThe Summit 200
Frisco, CO
August 2027
3 racesSeptember 2027
2 racesQuick answers
What is the next trail race or ultramarathon in Colorado?
Rocky's Backyard Ultra, on Saturday, October 10, 2026, in Estes Park. Distances: Backyard Ultra.
How many trail races and ultramarathons in Colorado have open registration?
15 of the 44 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 trail races and ultramarathons in Colorado offer prize money?
2 races advertise prize money, including Rocky's Backyard Ultra ($1,000).
How many of the trail races in Colorado are ultramarathons?
30 of the 44 are ultramarathons (longer than a marathon, or a backyard, timed or 200+ mile format). The other 14 are shorter races.
What is the busiest month for trail races and ultramarathons in Colorado?
October 2026, with 11 of the 44. November 2026 follows with 11.
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