Colorado Trail Running Calendar 2025-2026

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Explore the best trail runs in Colorado for 2025-2026! Our updated list features 284 exciting races across the region. Find your next race in Colorado below and join the running community at these great events!

April 2026
Apr
10-12
Fr - Su

Desert Rats Trail Running Festival

Trail Run 9 km 21 km 48 km 100 km
Apr
10-11
Fr - Sa

Run The Ranch

Trail Run 5 km 10 km ... 6 hr 12 hr
Apr
12
Sunday

Donut Dash - Denver

5 km
Apr
12
Sunday

Platte River Half-Marathon

13 mi
Apr
18
Saturday

Rattler Trail Race

Trail Run 5 km 10 km 25 km 50 km
Apr
18
Saturday

All-Out Beat the Heat

5 km 10 km 13 mi
Apr
19
Sunday

Horsetooth Half Marathon

13 mi
Apr
25
Saturday

Runs With Scissors Races

13 mi 26 mi 50 km
Apr
25
Saturday

The Best Races - Centennial

5 km 10 km 13 mi
Apr
26
Sunday

Unicorn 5k

2 mi 5 km
May 2026
May
2
Saturday

Greenland Trail Races

Trail Run 4 mi 8 mi 25 km 50 km
May
2-9
Sa - Sa

Niwot's Challenge

Trail Run 24 mi 50 mi 100 mi
May
2
Saturday

Take 5 in The Garden

Trail Run 5 km 5 mi
May
3
Sunday

Colorado Marathon

5 km 10 km 13 mi 26 mi
May
3
Sunday

The Pilgrimage

Trail Run 6 mi 11 mi 12 mi
May
9
Saturday

Valkyrie Trail Race

Trail Run 4 mi 8 mi ... 26 mi 50 km
May
10
Sunday

Colorado Women's Classic

5 km 10 km 10 mi
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
May
30-31
Sa - Su

Colorado Springs Spartan Trifecta Weekend

Obstacle Run 5 km 10 km 21 km 50 km
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