Colorado Marathon Calendar 2025-2026

Header image

Explore the best marathons in Colorado for 2025-2026! Our updated list features 24 exciting races across the region. Find your next race in Colorado below and join the running community at these great events!

May 2026
May
3
Sunday

Colorado Marathon

5 km 10 km 13 mi 26 mi
May
9
Saturday

Valkyrie Trail Race

Trail Run 4 mi 8 mi ... 26 mi 50 km
May
16
Saturday

Endure Trail Runs

Backyard Ultra 10 km 13 mi 26 mi 12 hr
May
16-17
Sa - Su

Denver Colfax Marathon

10 mi 13 mi 26 mi
Articles
Top 10 Marathons in the Netherlands — The Ultimate Dutch Marathon Bucket List: 10 Unmissable Races
The Beauty of the Easy Run — Why slowing down might be the smartest thing you do for your running
Mizuno Wave Rider 28: Elevating the Legacy of a Running Icon
Garmin Forerunner Review: Garmin Forerunner Series