Ultramarathons Near Boulder, CO
As of October 6, 2026, Crewable lists 13 upcoming ultramarathons near Boulder, CO from October 2026 to September 2027. The next is Rocky's Backyard Ultra on October 10 in Estes Park, CO. Registration is open for 4. 2 advertise prize money.
Sources: UltraSignup, RunSignUp, UTMB, race organizers and race websites
With aid station data
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
1 aid
1 aidRace calendar
October 2026
5 racesBlue Sky Trail Marathon & Half Marathon
Fort Collins, CO3,500 ft gainMarathonHalf MarathonOpen until Oct 17from $110
November 2026
3 racesDecember 2026
2 racesMay 2027
1 raceAugust 2027
1 raceSeptember 2027
1 raceQuick answers
What is the next ultramarathon near Boulder, CO?
Rocky's Backyard Ultra, on Saturday, October 10, 2026, in Estes Park, CO. Distances: Backyard Ultra.
What is the closest ultramarathon to Boulder?
The Barnyard Backyard Ultra in Erie, CO, about 15 miles from Boulder, on October 24, 2026.
How many ultramarathons near Boulder, CO have open registration?
4 of the 13 list registration as open as of October 6, 2026, including Blue Sky Trail Marathon & Half Marathon, Indian Creek Trail Runs and Colorado 24 Hour Run.
Which ultramarathons near Boulder, CO offer prize money?
2 races advertise prize money, including Rocky's Backyard Ultra ($1,000).
What is the busiest month for ultramarathons near Boulder, CO?
October 2026, with 5 of the 13. November 2026 follows with 3.
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