Colorado Marathon Calendar 2025-2026

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Explore the best marathons in Colorado for 2025-2026! Our updated list features 16 exciting races across the region. Find your next race in Colorado below and join the running community at these great events!

October 2025
Oct
18-19
Sa - Su

Blue Sky Trail Marathon

Trail Run Half Marathon Marathon
November 2025
Nov
2
Sunday

Rim Rock Marathon & Half Marathon

13 mi 26 mi
March 2026
Mar
14
Saturday

Run Through Time Trail Marathon

Trail Run 2 mi Half Marathon Marathon
April 2026
Apr
25
Saturday

Runs With Scissors Races

Half Marathon Marathon 50 km
May 2026
May
3
Sunday

Colorado Marathon

5 km 10 km Half Marathon Marathon
May
9
Saturday

Valkyrie Trail Race

Trail Run 4 mi 8 mi ... Marathon 50 km
May
15-17
Fr - Su

Denver Colfax Marathon

5 km 10 mi 13 mi 26 mi
May
16
Saturday

Endure Trail Runs

Backyard Ultra 10 km Half Marathon Marathon 12 hr
June 2026
Jun
6
Saturday

Summits Trail Runs

Trail Run 6 mi 13 mi Marathon 50 km
Jun
7
Sunday

Steamboat Marathon

10 km Half Marathon Marathon
Jun
27
Saturday

Leadville Trail Marathon and Heavy Half

Trail Run 15 mi 26 mi
July 2026
Jul
18
Saturday

Silverton Alpine Runs

Trail Run 8 mi Marathon 50 km
Jul
19
Sunday

Aspen Valley Marathon

5 km Half Marathon Marathon
August 2026
Aug
1
Saturday

Aspen Backcountry Marathon

Trail Run Half Marathon Marathon 50 km
September 2026
Sep
27
Sunday

Run Boulderthon: The Boulder Marathon

5 km 10 km Half Marathon Marathon
October 2026
Oct
3
Saturday

Colorado Springs Marathon

5 km Half Marathon Marathon
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