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Colorado Half Marathon Calendar

Browse all Colorado Half Marathons in 2025 and 2026 by month and by city below. For each race, you’ll find the history of the half marathon and the course, the most recent year’s course maps, elevation profiles, runner reviews, pricing, and how to sign up.

We dedicate hours every month searching for races to include in the Colorado Half Marathons calendar. If you happen to see any half marathon not included, contact us at [email protected] to submit your race.

Valkyrie Trail Race Half Marathon course in Colorado Springs, CO

Filter Colorado Half Marathons

Filter Colorado Half Marathons

Slacker Half Marathon
June 28, 2025
1,000-10,000 runners
Georgetown, Colorado
July 4, 2025
100-500 runners
Castle Rock, Colorado
Colorado Brewery Running Series Logo
July 6, 2025
100-500 runners
Wheat Ridge, Colorado
Race in the Clouds- Dirt Festival Logo
July 12, 2025
100-500 runners
Alma, Colorado
July 12, 2025
1-100 runners
Westminster, Colorado
July 19, 2025
100-500 runners
Aspen, Colorado
July 19, 2025
100-500 runners
Castle Rock, Colorado
Powderhorn Mountain Ultra, Vertical Challenge and relay logo
July 19, 2025
100-500 runners
Mesa, Colorado
Emerald Mountain Epic Marathon & Half Marathon logo
August 2, 2025
100-500 runners
Steamboat Springs, Colorado
August 2, 2025
100-500 runners
Arvada, Colorado
Boulder Rez Marathon logo
August 2, 2025
100-500 runners
Boulder, Colorado
Rocky Mountain Half Marathon logo
August 2, 2025
1,000-10,000 runners
Estes Park, Colorado
Hero Hustle Logo
August 2, 2025
100-500 runners
Colorado Springs, Colorado
Popsicle 5K, 10K and Half Marathon Logo
August 2, 2025
100-500 runners
Colorado Springs, Colorado
Sheep Mountain Trail Runs Logo
August 2, 2025
100-500 runners
Fairplay, Colorado
I'm Bound for Boston Marathon & Half Marathon - Denver Logo
August 3, 2025
100-500 runners
Denver, Colorado
Choice City Running Festival - Mountain Avenue Mile & Human Race Logo
August 9, 2025
100-500 runners
Fort Collins, Colorado
Frisco, CO
August 9, 2025
100-500 runners
Frisco, Colorado
Georgetown to Idaho logo
August 9, 2025
500-1000 runners
Georgetown, Colorado
August 9, 2025
100-500 runners
Fort Collins, Colorado

Running in Colorado

FAQ

What are the most popular Colorado half marathons?

The four most popular Colorado half marathons are the Denver Colfax Half Marathon, the REVEL Rockies Half Marathon, the Horsetooth Half Marathon, and Boulderthon.

What’s the best half marathons in Colorado for beginners in 2025?

We have three picks for the best beginner Colorado half marathons. The first is the Slacker Half Marathon for it’s fun fast downhill course. Secondly, Boulderthon, for it’s scenic course, huge crowds, and amazing production quality. And finally, the Denver Colfax Half Marathon for it’s notable and exciting course and race experience.

Which months can I run a half marathon in Colorado?

You can run a half marathon in Colorado in January, February, April, May, June, July, August, September, October, November, and December.

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