Race Collection
Half Marathons in Colorado
There are 5 upcoming half marathons in Colorado on the 42Cal calendar, from September 2026 through June 2027. Course elevation gain starts as low as 591 ft, with a median of 692 ft across the field.
5
Upcoming races
September 2026 – June 2027
Date range
1
Countries
692 ft
Median elevation
Race data last updated .
The Races
5 races
Sep 27, 2026
Registration Open
Boulderthon
Boulder, Colorado, United States
Marathon
Also: Half Marathon, 10K, 5K
See full guide
Apr 18, 2027
Registration Open
Horsetooth Half Marathon
Fort Collins, CO, United States
Half Marathon
See full guide
May 2, 2027
Opening Soon
Colorado Marathon
Fort Collins, CO, United States
Marathon
Also: 5K, 10K, Half Marathon
See full guide
May 16, 2027
Opening Soon
Colfax Marathon
Denver, CO, United States
Marathon
Also: Half Marathon, 5K
See full guide
Jun 6, 2027
Opening Soon
Steamboat Marathon
Steamboat Springs, Colorado, United States
Marathon
Also: Half Marathon, 10K
See full guide
Compare These Races
| Race | Date | Location | Distance | Elevation | Status |
|---|---|---|---|---|---|
| Boulderthon | September 2026 | Boulder, United States | Marathon | 603 ft | Registration Open |
| Horsetooth Half Marathon | April 2027 | Fort Collins, United States | Half Marathon | 280 m | Registration Open |
| Colorado Marathon | May 2027 | Fort Collins, United States | Marathon | 180 m | Opening Soon |
| Colfax Marathon | May 2027 | Denver, United States | Marathon | 211 m | Opening Soon |
| Steamboat Marathon | June 2027 | Steamboat Springs, United States | Marathon | 736 ft | Opening Soon |
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