The Colfax 5K is a fast, flat loop through City Park — Denver's crown jewel. Perfect for first-time racers, families, and speed demons looking to PR at altitude.

Starting at 7:30 AM (after the longer distances), you'll have the energy of thousands of spectators already cheering on marathon runners. The 5K finishes at the same Ferril Lake finish line, giving you the full Colfax experience in 3.1 miles.

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.