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Colorado Marathon Calendar 2026-2027

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Monthly updates for Colorado

Get new running races (and updates) in your inbox every month.

Explore the best marathons in Colorado for 2026-2027! Our updated list features 26 exciting races across the region. Find your next race in Colorado below and join the running community at these great events!

March 2026
Mar
14
Sa

Run Through Time Trail Marathon

Trail Run 2 mi 13 mi 26 mi
April 2026
Apr
25
Sa

Runs With Scissors Races

Half Marathon Marathon 50 km
May 2026
May
3
Su

Colorado Marathon

5 km 10 km Half Marathon Marathon
May
9
Sa

Valkyrie Trail Race

Trail Run 4 mi 8 mi ... Marathon 50 km
May
16
Sa

Endure Trail Runs

Backyard Ultra 10 km Half Marathon Marathon 12 hr
May
17
Su

Denver Colfax Marathon

10 mi Half Marathon 26 mi
May
24
Su

Spirit Trail Run

Trail Run 9 km Half Marathon Marathon
May
30-31
Sa - Su

Weld Your Mettle Running Festival

Backyard Ultra 4 mi 14 mi ... 100 km 100 mi
June 2026
Jun
6
Sa

Summits Trail Runs

Trail Run 6 mi 13 mi ... 50 km 14 hr
Jun
7
Su

Steamboat Marathon

10 km Half Marathon Marathon
Jun
20
Sa

Estes Park Marathon

5 mi Half Marathon Marathon
Jun
27-28
Sa - Su

Leadville Trail Marathon and Heavy Half

Trail Run 15 mi 26 mi
July 2026
Jul
18
Sa

Silverton Alpine Runs

Trail Run 8 mi Marathon 50 km
Jul
19
Su

Aspen Valley Marathon

5 km Half Marathon Marathon
August 2026
Aug
1
Sa

Aspen Backcountry Marathon

Trail Run Half Marathon Marathon 50 km
Aug
2
Su

Bound for Boston Marathon - Denver

Half Marathon Marathon
Aug
8-9
Sa - Su

Emerald Mountain Epic

Trail Run 13 mi 26 mi
Aug
15
Sa

Boulder Rez Marathon

Trail Run 10 km Half Marathon 31 km Marathon
Aug
22
Sa

Staunton Rocks

Trail Run 13 mi 26 mi
September 2026
Sep
11-12
Fr - Sa

American Heroes Run

Trail Run 5 km 9 mi ... 100 mi 24 hr