Marathons in Colorado, United States
56 upcoming races are listed in Colorado, including 24 marathons, 41 half marathons and 17 ultras. The next is Center of the Nation - CO on September 29, 2026.
October has the most races. Race pages link the official source where we have one. Confirm dates and prices with the organizer before you register.
56
Races listed
24
Marathons
October
Busiest month
25 May
Last updated
| Date | Race | City | Distances | From |
|---|---|---|---|---|
| 29 Sep 2026 29Sep 26 | Center of the Nation Series - Day 2 (CO) | Colorado | 42.2K · 21.1K | - |
| 29 Sep 2026 29Sep 26 | Center of the Nation - CO | Sterling | 42.2K | - |
| 3 Oct 2026 03Oct 26 | Colorado Springs Marathon, Half, 5K, and Kids K | Colorado Springs | 42.2K · 21.1K · Virtual | - |
| 3 Oct 2026 03Oct 26 | Outlast Denver | Littleton | 6 Hour | - |
| 3 Oct 2026 03Oct 26 | Rim to Rim Royal Gorge Races: 5K Road Run, Trail 8 Mile, Trail Half Marathon | Canon City | 21.1K · 8 Miler · 5K | - |
| 3 Oct 2026 03Oct 26 | Spooky Sprint - Denver | Littleton | 21.1K · 10K · 5K | - |
| 3 Oct 2026 03Oct 26 | West Elk Challenge | Crawford | 42.2K · 30K | - |
| 4 Oct 2026 04Oct 26 | Boulder Marathon | Boulder | 42.2K · 21.1K · 10K | $85–$125 |
| 4 Oct 2026 04Oct 26 | Windsor Marathon, Half Marathon, 10k, 5k & 1 Mile Run | Windsor | 42.2K · 21.1K · 10K | - |
| 10 Oct 2026 10Oct 26 | Bagel Run 5K/10K/13.1 DENVER/AURORA | Centennial | 42.2K · 21.1K · 10K | - |
| 10 Oct 2026 10Oct 26 | Breckenridge RunFest | Breckenridge | 42.2K · 21.1K · 10K | - |
| 10 Oct 2026 10Oct 26 | Suffer Better 10th Annual Fall Trail Runs | Pine | 50K · 25K · 5K | - |
| 10 Oct 2026 10Oct 26 | The Long View Marathon | Fort Collins | 42.2K · 21.1K · 5K | - |
| 11 Oct 2026 11Oct 26 | Breckenridge Road Marathon | Breckenridge | 42.2K · 21.1K | - |
| 11 Oct 2026 11Oct 26 | Durango Marathon | Durango | 42.2K · 21.1K · 5K | - |
| 11 Oct 2026 11Oct 26 | Run the Rocks Park and Amphitheatre | Colorado | Ultra | - |
| 11 Oct 2026 11Oct 26 | Westy Half & 5k | Westminster | 21.1K · 5K | - |
| 17 Oct 2026 17Oct 26 | Blue Sky Marathon | Colorado | 42.2K | - |
| 17 Oct 2026 17Oct 26 | Bobcat Trail Races | Colorado Springs | 50K · 25K · 10K | - |
| 18 Oct 2026 18Oct 26 | Denver Marathon | Denver | 42.2K · 21.1K · 10K | $85–$130 |
| 19 Oct 2026 19Oct 26 | Blue Sky Trail Marathon | Colorado | Ultra · 42.2K | - |
| 31 Oct 2026 31Oct 26 | PB&J Fuel Run 5K/10K/13.1 DENVER/AURORA | Centennial | 42.2K · 21.1K · 10K | - |
| 31 Oct 2026 31Oct 26 | Spooky Sprint - Colorado Springs | Colorado Springs | 21.1K | - |
| 1 Nov 2026 01Nov 26 | All-Out Kooky-Spooky | Golden | 21.1K · 10K · 5K | - |
Go a level deeper
Links go down the map, not sideways. Each region and city has its own page of races.
Cities
Common questions
When is the next race in Colorado?
Center of the Nation - CO on September 29, 2026. The table above lists every upcoming race in date order.
Which months are busiest in Colorado?
October (21), November (13), December (6), counting every upcoming race listed in Colorado.
Which distances can I run in Colorado?
The listed races include 24 marathons, 41 half marathons, 17 ultras, 25 10Ks and 30 5Ks. Many events offer more than one distance on the same day.
How do I confirm a race’s details?
Open the race page and check its provenance ledger, which shows where each fact came from. Then confirm the date, price and entry rules with the organizer before you register or book travel.
Spotted something wrong on this page?
Dates and prices move · tell us and we check the organizer’s source