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Marathon Calendar near Boulder Reservoir 2026-2027

Monthly updates for Boulder Reservoir

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

Explore the top marathons near Boulder Reservoir for 2026-2027! We've gathered 6 exciting races in the area. Check out our detailed list below to find your next local race.

April 2026
Apr
25
Sa

Runs With Scissors Races

13 mi 26 mi 50 km
May 2026
May
15-17
Fr - Su

Denver Colfax Marathon

5 km 10 mi Half Marathon Marathon
June 2026
Jun
21
Su

Estes Park Marathon

5 mi 13 mi 26 mi
August 2026
Aug
15
Sa

Boulder Rez Marathon

Trail Run 10 km Half Marathon 31 km Marathon
September 2026
Sep
11-12
Fr - Sa

American Heroes Run

Trail Run 5 km 9 mi ... 100 mi 24 hr
Sep
27
Su

Run Boulderthon: The Boulder Marathon

5 km 10 km Half Marathon Marathon