You can run Colorado half-marathon events in Arvada, Aspen, Bayfield, Beulah, Boulder, Breckenridge, Brighton, Buena Vista, Canon City, Castle Rock, Centennial, Cheyenne, Colorado Springs, Denver, Divide, Durango, Erie, Estes Park, Firestone, Four Corners Monument, Frisco, Fruita, Georgetown, Golden, Granby, Grand Junction, Highlands Ranch, Lakewood, Longmont, Louisville, Nederland, Ouray, Parker, Pending, Pine, Provo, Pueblo, Red Feather Lakes, Salt Lake City, Steamboat Springs, Telluride, Trinidad, Westminster, and Windsor.
Upcoming Half Marathons Near Longmont, CO
Looking for a half marathon in Longmont, Colorado? Browse the most comprehensive Longmont half marathon calendar with each race history, course description, difficulty rating, finisher ranges, scenery, and what the race is perfect for like family-friendly or lots of crowd support.
You’ll also be able to find must-know race logistics like pricing, start time, and course maps.
Half marathons are always coming and going. If you don’t see a race on the Longmont half marathon calendar, you can contact us at [email protected].
Filter Colorado Half Marathons
Race Size
Difficulty
Scenery
Type
Perfect For
Distances
Filter Colorado Half Marathons
Race Size
Difficulty
Scenery
Type
Perfect For
Distances
December 6, 2025
1-100 runners
Westminster, Colorado
- 10K, 5k, Half Marathon, Road
January 18, 2026
100-500 runners
Westminster, Colorado
- 10K, 5k, Half Marathon, Road
April 11, 2026
100-500 runners
Boulder, Colorado
- 10K, 5k, Half Marathon, Trail
April 18, 2026
1-100 runners
Westminster, Colorado
- 10K, 5k, Half Marathon, Marathon, Trail & Road
April 25, 2026
1-100 runners
Brighton, Colorado
- Half Marathon, Marathon, Trail, Ultramarathon
May 3, 2026
100-500 runners
Longmont, Colorado
- 5k, Half Marathon, Trail
June 7, 2026
100-500 runners
Louisville, Colorado
- 10K, 5k, Half Marathon, Trail
July 11, 2026
1-100 runners
Westminster, Colorado
- 10K, 5k, Half Marathon, Road
August 16, 2026
1-100 runners
Erie, Colorado
- 5k, Half Marathon, Trail
August 23, 2026
100-500 runners
Westminster, Colorado
- 10K, 5k, Half Marathon, Road
September 19, 2026
1-100 runners
Westminster, Colorado
- 10K, 5k, Half Marathon, Marathon, Road
September 27, 2026
1,000-10,000 runners
Boulder, Colorado
- Half Marathon, Marathon, Road
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 Colorado cities have half marathons?
