JOIN OUR 20TH YEAR! - and celebrate the largest marathon weekend in the Rocky Mountain Region
New for our 20th Year! “WOW” at Every Mile
To celebrate our 20th, every mile will have a WOW for runners. That moment every mile that gives you that WOW and extra energy for the miles to come.
We are inviting local musicians, artisans, drumlines, choirs, … to be part of our WOW for our 20th Year Celebration. You can apply now by emailing Wally@RunColfax.org as spots are filling fast!
We welcome runners, spectators, volunteers, and entertainers to join the largest Marathon Weekend in the Rocky Mountain states
Check out our 20th Year jackets
Limited supply so purchase one now. Women’s sizes in Coral Reef or Black. Men’s/Unisex sizes in Ocean Teal or Black. Check out enlarged images here. You can purchase one when you Register. OR you can shop any time at our Colfax Store
Denver Colfax Marathon Weekend Details
Two Days, Eight Races
Save the Date for 2026! We are excited to host the Denver Colfax Marathon May 15-17, 2026. We’ll have our two-day Cigna Denver Colfax Marathon Expo at Empower Field at Mile High on Friday and Saturday. Our 5K Kickoff will be on Saturday May 16th, and our main Race Day will be on Sunday May 17th for the Marathon, Half Marathon, Urban 10 Miler and Marathon Relay (Corporate, Government, Public Schools, and Open Relay Divisions).
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Denver's Only Marathon
Where to start? Boston Qualifier, through Empower Field at Mile High twice, along miles of water, through a fire station, & ranked by Runner’s World! Finish your 26.2 into a huge post-race party with live music, food, & drinks.
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Half Marathon Course - Downtown & a NEW Denver Zoo Mile
The animals at Denver Zoo will be your spectators for a full mile of this great half marathon course. Elephants, giraffes, zebras, monkeys, and many more will be watching your “personal safari” for a full mile. You’ll have one mile in Denver Zoo, plus you’ll run along Colfax with epic spots like VooDoo Donuts, by the Capitol, inside Denver Fire Station #1, and along 17th Avenue into an awesome finish party with 25,000 new friends!
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Marathon Relay - Open, Corporate, Gov't, Public School Teachers
What’s better than running 26.2 miles through the Mile High City? Sharing the miles with friends! Get a team of five to run Denver’s only 26.2 mile Marathon Relay. Most teams run for fun. Others run for bragging rights and money for charity.
It’s the largest in the US – because of the fun! Companies and government entities enter multiple teams in their industry division – like Construction, Healthcare, or Public School Teachers. Friends enter the Open Division.
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A Competition of Corporate Giving
Denver Business Journal named in a recent year the Colfax Marathon “Denver’s corporate “it” charity of the year”, with an average of $150,000 awarded annually to charities through the Open, Corporate, and Government Relay divisions. Get your company teams together now!
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Urban 10 Miler - a local's favorite
It’s the marathon course in just 10 miles! Perfect if you love the idea of running downtown, through the stadium, eclectic college campus, and waterways – but do not want to tackle a full 26.2 miles. It’s a point to point race, that starts a bit later at RMCAD, and then finishes with the marathon, half, and relay in City Park. Your bib has an RTD ticket to get back to your car. A Denver favorite!
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