Colorado · September
September Races in Colorado
Find races in Colorado taking place in September. Compare dates, locations, distances and registration information. Explore 16 race with a confirmed dates.
- Upcoming, date confirmed
- 16
- Active listings
- 110
Nearby months
Browse Colorado races by distance
Races in nearby states
Guides from the RaceRove blog
- 8 min read How to Choose the Best Half Marathon for a PR, Racecation or 50-State Challenge The best half marathon depends on what you want from it. How to choose a course for a personal record, a race worth travelling for, or an efficient stop on a 50-state challenge.
- 4 min read Diplo's Run Club 2026-27: Every City, Date and Course Diplo's Run Club is a 5K with a post-race concert. Every US date for 2026-27 (San Francisco, New York, Los Angeles, San Diego and Phoenix), start times and courses.
- 8 min read How to Choose Your First Marathon A practical checklist for choosing a first marathon based on course, weather, cutoff, travel, field size and support.
- Blog All guides Planning advice for finding, choosing and travelling to races.
September Races in Colorado: common questions
- How many races are there in Colorado in September?
- RaceRove currently lists 16 upcoming races in Colorado in September with a confirmed date, plus 94 annual events usually held that month whose next date hasn't been announced yet.
- What is the biggest race in Colorado in September?
- By estimated field size, the largest event is the Boulder Marathon, with about 15,000 runners across all of its distances.
Search every race in Colorado
Filter by month, distance, course profile and field size, save races to a shortlist and compare them side by side in the interactive search.