Half marathons in Colorado — September 2026
12 upcoming half marathons in Colorado during September 2026.
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This calendar currently lists 12 upcoming events, from Sep 12, 2026 to Sep 27, 2026. September is the busiest month, with 12 events scheduled. Events are spread across 10 different locations; Nederland hosts the most (2). Course distances range from 11 km to 21.1 km.