The Colfax 10 Miler is the most unique distance in the Colfax family. The western loop takes runners through downtown Denver, past Empower Field at Mile High (with the famous stadium run-through), and along Sloan's Lake with panoramic Rocky Mountain views.

At 10 miles, it's a step up from a 10K but less daunting than a half marathon — the sweet spot for many runners.

Altitude Advisory: At 5,280 feet, oxygen levels are about 17% lower than at sea level. Arrive 2–3 days early, increase water intake by 50%, and start conservatively.

Ready to Run?

Registration for the 2026 Denver Colfax Marathon is open.