Course Map
About this Race
The Denver Colfax Marathon is Denver's flagship road race, run a full mile above sea level along Colfax Avenue and through City Park in the Colorado capital. The course is fairly runnable underfoot, but the thin high-altitude air is the defining challenge, punishing anyone who ignores it early. Held in May, it typically offers mild spring conditions well suited to the effort the altitude demands. The crowds are enthusiastic along the historic Colfax strip. It suits runners who want a genuine mile-high challenge and are prepared to respect the thin air over a fast personal best.
Course Insight
Colfax is the Mile-High marathon, and that altitude around 1,600 metres is the defining feature, thinning the air enough to punish any sea-level pace. Throw out your usual splits and run by effort, going out deliberately easy through the flat Denver streets. The thin air bites hardest if you push early. May conditions are otherwise runnable. Respect the altitude from the gun and you'll finish strong rather than fading.
Difficulty Breakdown
Mostly due to tough late hills, meaningful altitude, lots of turns.
Course Details
- Course type
- Loop
- Elevation gain
- 215m
- Elevation loss
- 215m
- Highest point
- 1691m
- Lowest point
- 1579m
- Net elevation
- +112m
- Start
- East side of Ferril Lake in City Park
- Cutoff time
- 6h 0m
Race History
The Colfax Marathon was first held in 2006 as Denver's flagship road race, run a full mile above sea level where the thin Colorado air is the defining challenge. Its course along Colfax Avenue and through City Park built its identity around the high-altitude test. From its founding it grew into the Mile High City's signature marathon. Held each May, it draws a field to the Colorado capital.
Plan Your Trip
Everything you need to know to get there, get settled, and get to the start line.
- Nearest airport(s)
- Denver International (DEN)
- Best area to stay
- LoDo downtown for proximity to the route and full hotels, the City Park area for proximity to the course, and Capitol Hill for characterful, value stays.
- Getting to the start
- The start is in City Park; take the RTD light rail or a short rideshare to the park, or walk from nearby neighbourhoods.