Which Colorado cities have the most ultramarathons?
Larkspur (1), Divide (1), Eaton (1), Fairplay (1) lead the state for Ultra races. Those give you the most dates to choose from if your schedule is tight.
Colorado · Ultra
2027 Ultramarathons in Colorado
Every upcoming Ultra in Colorado, all 5 of them, sorted by date. Dates, entry fees, finish-time stats from past results, and start-line maps.
5 upcoming ultramarathons · 2 with finish-time stats
By the numbers
The Biggest and Longest-Running
The Colorado races that stand out on the numbers: the biggest field, and the longest unbroken run of editions.
Colorado Ultramarathons by City
The Next Ultra Marathons in Colorado
5 total Sat, May 1, 2027Greenland Trail Races Larkspur, COFrom $35Details Sat, May 15, 2027Endure Trail Runs Divide, CORegistration opens Dec 1From $100Details Sat, Jun 5, 2027Weld Your Mettle Running Festival Eaton, COFrom $80Details Sat, Aug 7, 2027Sheep Mountain Trail Runs Fairplay, CORegistration opens Dec 1From $130Details Sat, Sep 25, 2027Sangre de Cristo Trail Festival Westcliffe, CORegistration opens Dec 1From $130Details
How we calculate these stats: RunSesh calculates these figures from the most recent published results of past editions, sourced from RunSignup. We show aggregates only: field size, winning and median times, and the cutoff. We never publish individual finisher tables. Last updated Oct 25, 2026.
Common Questions About Running an Ultra in Colorado
When are most ultramarathons held in Colorado?
May is the busiest month for Ultra races in Colorado, with 2 of the 5. If you are flexible on the date, that is the quickest way to narrow things down.
Are there trail Ultra races in Colorado?
Yes, 5 races around Colorado get you off the pavement: 5 are trail races.