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Half Marathon Calendar near Longmont 2026-2027

Monthly updates for Longmont

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

Explore the top half marathons near Longmont for 2026-2027! We've gathered 39 exciting races in the area. Check out our detailed list below to find your next local race.

January 2026
Jan
10
Sa

Polar Prowl

5 km 10 km Half Marathon
February 2026
Feb
15
Su

Ralston Creek Half Marathon

5 km Half Marathon
Feb
22
Su

Mardi Crawl

5 km 10 km Half Marathon
March 2026
Mar
14
Sa

Lucky Brew Race 15K

5 km 10 km 15 km Half Marathon
Mar
22
Su

All-Out Spring Fever

5 km 10 km Half Marathon
April 2026
Apr
11
Sa

Boulder Rez Half

3 mi 6 mi 13 mi
Apr
12
Su

Spring Fling Prairie Dog Half Marathon

5 km 10 km Half Marathon
Apr
18
Sa

All-Out Beat the Heat

5 km 10 km Half Marathon
Apr
19
Su

Horsetooth Half Marathon

Half Marathon
Apr
25
Sa

Runs With Scissors Races

Half Marathon Marathon 50 km
Apr
25
Sa

Bigfoot Half Marathon

5 km Half Marathon
Apr
26
Su

Blue Heron Half Marathon

5 km 13 mi
May 2026
May
3
Su

Colorado Marathon

5 km 10 km Half Marathon Marathon
May
3
Su

Longmont Half

5 km 13 mi
May
9
Sa

Carbon Valley Half Marathon

5 km 13 mi
May
17
Su

Denver Colfax Marathon

10 mi Half Marathon 26 mi
June 2026
Jun
7
Su

Colorado 13er Half Marathon

5 km 10 km 13 mi
Jun
13
Sa

All-Out Summer Breeze

5 km 10 km 13 mi
Jun
13
Sa

Barr Lake Trail Race

Trail Run 5 km 15 km ... 30 km 50 km
Jun
20
Sa

Red, White and Brew Half Marathon

5 km 10 km Half Marathon