Colorado · Marathon · Half Marathon · 10K
Boulderthon
Boulderthon is a marathon, half marathon, 10K, 5K and Kids Run event held in Boulder, Colorado. It is usually held in September; the exact date hasn't been confirmed in the listing yet. About 15,000 runners take part across all distances.
- Usually held
- September
- Location
- Boulder, CO
- Field size
- ~15,000 runners
Race details
- Usually held in
- September (date not confirmed)
- Location
- Boulder, Colorado
- Distances
- Marathon, Half Marathon, 10K, 5K, Kids Run
- Field size
- About 15,000 runners
- Course
- ~5,300 ft base elevation at the foot of the Flatirons; rolling start/finish in downtown Boulder
- Registration
- letsdothis.com
- Official website
- boulderthon.org
About the Boulderthon
Colorado's largest fall race weekend, with marathon-through-5K distances starting and finishing on Boulder's Pearl Street Mall beneath the Flatirons.
Rankings and notes
- Rankings and awards
- Billed as Colorado's largest fall race series and one of the largest September running weekends in the U.S.; draws runners from all 50 states and 20+ countries
More marathons in Colorado
Coming up next, by confirmed date.
-
Colorado Springs Marathon, Half, 5K, and Kids KColorado Springs, COMarathonHalf Marathon10K5K +1 more
-
Windsor Marathon, Half Marathon, 10k, 5k & 1 Mile RunWindsor, COMarathonHalf Marathon10K5K +1 more ~660 runners
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Guides from the RaceRove blog
- 7 min read How to Find a 5K, 10K, Half Marathon or Marathon Near You A practical way to find running races near you: pick a distance, decide how far you'll travel, read the listing properly and confirm the details before you register.
- 9 min read How to Run a Race in All 50 States How to plan a 50-state running challenge: set your own rules, group states into trips, build a calendar around the seasons, budget for it and keep track of every finish.
- 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.
- Blog All guides Planning advice for finding, choosing and travelling to races.
Boulderthon: common questions
- When is the Boulderthon?
- The next date hasn't been announced in the listing yet. The race is usually held in September. Check the organiser's website for the official date.
- Where is the Boulderthon held?
- In Boulder, Colorado.
- What distances does the Boulderthon offer?
- Marathon, Half Marathon, 10K, 5K and Kids Run.
- How many people run the Boulderthon?
- About 15,000 runners across all of its distances. That figure is an estimate of the field size, not an entry cap.
- How do I register for the Boulderthon?
- Registration is handled by the organiser at letsdothis.com. Entry fees, caps and deadlines are set there.
Plan this race in RaceRove
Save it to your plan, compare it with other races, check typical race-day weather and track your 50-state progress in the interactive app.