Colorado Half Marathon Calendar 2025-2026

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Explore the best half marathons in Colorado for 2025-2026! Our updated list features 83 exciting races across the region. Find your next race in Colorado below and join the running community at these great events!

March 2026
Mar
22
Sunday

All-Out Spring Fever

5 km 10 km 21 km
April 2026
Apr
4
Saturday

The Best Races - Centennial

5 km 10 km 13 mi
Apr
10-12
Fr - Su

Desert Rats Trail Running Festival

Trail Run 9 km 21 km 48 km 100 km
Apr
12
Sunday

Platte River Half-Marathon

21 km
Apr
12
Sunday

Spring Fling Prairie Dog Half Marathon

5 km 10 km 13 mi
Apr
18
Saturday

All-Out Beat the Heat

5 km 10 km 21 km
Apr
18
Saturday

Great Western Trail Race

Trail Run 5 km 10 km 21 km
Apr
19
Sunday

Horsetooth Half Marathon

21 km
Apr
25
Saturday

Runs With Scissors Races

21 km 42 km 50 km
Apr
25
Saturday

The Best Races - Centennial

5 km 10 km 13 mi
May 2026
May
3
Sunday

Colorado Marathon

5 km 10 km 21 km 42 km
May
3
Sunday

The Pilgrimage

Trail Run 7 mi 11 mi 12 mi 13 mi
May
3
Sunday

Longmont Half

5 km 21 km
May
9
Saturday

Valkyrie Trail Race

Trail Run 4 mi 8 mi ... 42 km 50 km
May
16
Saturday

Endure Trail Runs

Backyard Ultra 10 km 21 km 42 km 12 hr
May
16-17
Sa - Su

Denver Colfax Marathon

5 km 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
June 2026
Jun
7
Sunday

Steamboat Marathon

10 km 13 mi 26 mi
Jun
13
Saturday

Summits Trail Runs

Trail Run 6 mi 21 km ... 50 km 12 hr
Jun
13
Saturday

All-Out Summer Breeze

5 km 10 km 21 km
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