Colorado Half Marathons by Date • By City
Browse all 2021 Colorado half marathons by month below. For each race, you’ll find course maps, elevation profiles, runner reviews, and how to sign up.
When you view a race, you’ll also find contact info if you’re having problems with your registration or need to contact the race directors.
January 2021
| Sat Jan 9 | All-Out Polar Prowl Half Marathon 10K & 5K | Arvada CO |
February 2021
| Sat Feb 6 | All-Out Mardi Crawl Half Marathon 10K & 5K | Lakewood CO |
| Sun Feb 7 | Super Half Marathon & 5K | Colorado Springs CO |
March 2021
| Sun Mar 7 | That Dam Run Half Marathon 10K & 5K | Greenwood Village CO |
| Tue Mar 9 | Dust Bowl Series Marathon Half Marathon 10K & 5K – Day 5 | Lamar CO |
| Sat Mar 13 | Run Through Time Marathon Half Marathon & 2-Mile | Salida CO |
| Sun Mar 21 | All-Out Spring Fever Half Marathon 10K & 5K | Golden CO |
| Sun Mar 21 | Spring Equinox Half Marathon | Fort Collins CO |
April 2021
| Sat Apr 3 | Runs with Scissors Marathon Half Marathon & 50K | Brighton CO |
| Sat Apr 3 | Three Creeks Half Marathon | Denver CO |
| Sun Apr 11 | Spring Fling Prairie Dog Half Marathon 10K & 5K | Arvada CO |
| Sat Apr 17 | All-Out Beat the Heat Marathon Half Marathon 10K & 5K | Westminster CO |
| Sun Apr 18 | Desert RATS Trail Running Festival | Fruita CO |
| Sat Apr 24 | Westminster Trail Half Marathon 10K & 5K | Broomfield CO |
May 2021
| Sat May 1 | Fruita Trail Half Marathon | Fruita CO |
| Sun May 2 | Colorado Marathon Half Marathon 10K & 5K | Fort Collins CO |
| Sat May 8 | Carbon Valley Half Marathon | Firestone CO |
| Sat May 8 | Mine Shaft Half & Tommyknocker Ultras | Golden CO |
| Sat May 15 | Vallecito Lake Heavy Half | Bayfield CO |
| Sun May 23 | Barr Lake Half Marathon & 15K | Brighton CO |
| Sat May 29 | Valkyrie Trail Marathon Half Marathon 50K & 4-Mile | Colorado Springs CO |
June 2021
| Sat Jun 5 | Bergen Peak Half Marathon | Evergreen CO |
| Sat Jun 5 | Revel Rockies Marathon & Half Marathon | Evergreen CO |
| Sun Jun 6 | Boulder Rez Half Marathon 10K & 5K | Boulder CO |
| Sun Jun 6 | Colorado 13er Half Marathon 10K & 5K | Louisville CO |
| Sun Jun 6 | Steamboat Marathon Half Marathon & 10K | Steamboat Springs CO |
| Sat Jun 12 | South Park Trail Marathon & Half Marathon | Fairplay CO |
| Sat Jun 12 | Steamworks Half Marathon | Durango CO |
| Sat Jun 19 | Mountain Ridge Half Marathon & 10K | Highlands Ranch CO |
| Sun Jun 20 | Estes Park Marathon Half Marathon 10K & 5K | Estes Park CO |
| Sat Jun 26 | All-Out Summer Breeze Half Marathon 10K 5K & 1-Mile | Arvada CO |
| Sat Jun 26 | Slacker Half Marathon 4-Mile & Relay | Georgetown CO |
July 2021
| Sun Jul 4 | Longmont Half Marathon & 5K | Longmont CO |
| Sat Jul 17 | All-Out Dog Days Half Marathon 10K & 5K | Westminster CO |
| Sat Jul 17 | Prairie Dog Half Marathon 10K & 5K | Castle Rock CO |
| Sun Jul 18 | Black Hawk Half Marathon & 10K | Golden CO |
| Sun Jul 18 | Sunlight Showdown Half Marathon | Glenwood Springs CO |
| Sat Jul 31 | Rocky Mountain Half Marathon | Estes Park CO |
| Sat Jul 31 | Winter Park Half Marathon & 5K | Winter Park CO |
August 2021
| Sun Aug 8 | Emerald Mountain Epic Marathon & Half Marathon | Steamboat Springs CO |
| Sat Aug 14 | Boulder Rez Marathon 3/4 Marathon Half Marathon & 10K | Boulder CO |
| Sat Aug 14 | Run the Rockies Trail Half Marathon & 10K | Frisco CO |
| Sat Aug 21 | All-Out Runapalooza Half Marathon 10K & 5K | Arvada CO |
| Sat Aug 21 | Mount Sneffels Marathon & Half Marathon | Ouray CO |
| Sun Aug 22 | Erie Half Marathon & 5K | Erie CO |
| Sat Aug 28 | Louisville Trail Race Half Marathon 10K & 5K | Louisville CO |
| Sat Aug 28 | Thirsty 13 Half Marathon | Durango CO |
September 2020
| Sun Sep 6 | Breck Crest Mountain Marathon Half Marathon & 10K | Breckenridge CO |
| Mon Sep 7 | Labor Day Half Marathon | Parker CO |
| Sat Sep 12 | American Heroes Run Marathon Half Marathon Ultra & 5K | Longmont CO |
| Sat Sep 12 | Black Squirrel Half Marathon | Fort Collins CO |
| Sat Sep 12 | Mountain Ridge Half Marathon & 10K | Highlands Ranch CO |
| Sat Sep 19 | All-Out Fallfest Marathon Half Marathon 10K & 5K | Westminster CO |
| Sat Sep 19 | Camp 4 Coffee Cart to Cart Trail Race | Crested Butte CO |
| Sat Sep 19 | Mountain Rats Marathon Half Marathon & 50K | Eagle CO |
| Sat Sep 19 | Snow Mountain Ranch Trail Running Festival | Granby CO |
October 2020
| Sat Oct 3 | Castle Rock Trail Festival | Castle Rock CO |
| Sat Oct 3 | Mine Shaft Half Marathon & Tommyknocker Ultras | Golden CO |
| Sat Oct 3 | Spanish Peaks Half Marathon & Fun Run | La Veta CO |
| Sun Oct 4 | Long View Marathon & Half Marathon | Fort Collins CO |
| Sun Oct 11 | Boulderthon Marathon & Half Marathon | Boulder CO |
| Sun Oct 11 | Breckenridge Brewery Half Marathon | Littleton CO |
| Sun Oct 11 | Run Through Time Marathon Half Marathon & Fun Run | Salida CO |
| Sun Oct 11 | Windsor Half Marathon & Heavy 10K | Windsor CO |
| Sun Oct 25 | All-Out Kooky Spooky Half Marathon 10K & 5K | Golden CO |
November 2020
| Sat Nov 7 | Backcountry Wilderness Half Marathon | Highlands Ranch CO |
December 2020
| Sat Dec 5 | All-Out Fa La La Half Marathon 10K & 5K | Westminster CO |
| Sun Dec 6 | Rock Canyon Half Marathon | Pueblo CO |
