Registration Opens for 20th Denver Colfax Marathon

August 19, 2025

Denver, CO /ENDURANCE SPORTSWIRE/ – The Denver Colfax Marathon, presented by Cigna Healthcare, is proud to open registration for its 20th race weekend in the Mile High City. The marathon weekend will take place May 15-17, 2026, marking two decades of deep tradition in Denver.

This race weekend has evolved significantly since its inaugural marathon in 2006. The first event hosted 4,000 runners and the weekend has since grown into Denver’s largest running event of the year with more than 25,000 runners.

“This milestone year marks a historic moment in Denver,” said Andrea Dowdy, CEO of the Denver Colfax Marathon. “Denver’s only marathon weekend is now twenty years strong, and our community has embraced this race year after year. We’re grateful to be the finish line that has inspired so many runners to achieve their goals. We are excited to celebrate this memorable year with all of you!”

Registration for the 2026 marathon weekend opens on August 19, 2025. The race weekend will feature 8 races over 2 days (marathon, half marathon, urban 10 miler, 5K, 4 marathon relay divisions). The first 500 people to register for a race receive the best price of the season, along with a guaranteed spot to run in the 20th race weekend celebration.

The 2026 race weekend will also feature the return of Colorado Half Marathon Showdown. The marathon debuted this program in its 2025 race to support elite runners who live and train in Colorado. Local athletes (men and women) who run the half marathon have the chance to compete for close to $25,000 in cash prizes, placing this race on the map for professional runners in the Mile High.

“Over the many years as title sponsor, we’ve been fortunate to bear witness to the remarkable impact the Denver Colfax Marathon has had on both participants and the community at large,” said Brett Winingham, market growth leader for Cigna Healthcare Mountain States. “Whether you are in a relay race, the full marathon or just there to cheer on a loved one running in an event, there is truly something in it for everyone. We look forward to being part of this 20^th race weekend and continuing to support the health and vitality of the people we serve.”

Since the marathon’s inception, the Denver Colfax Marathon has hosted hundreds of thousands of runners in the Mile High. These runners have raced a total of 3 million miles throughout the city in 20 years. The marathon is proud to have worked with over 700 charities in its Charity Partners Program, which is one of the largest race nonprofit platforms in the county. This program has had a 10-million-dollar impact on the local nonprofit community as it helps each charity raise awareness and funds for their cause.

The Denver Colfax marathon race weekend is the largest marathon weekend in the 8 state Rocky Mountain Region and a top 25 marathon weekend in the country. The 2026 race weekend is expecting more than 25,000 runners for its 20th year. You can register for a race at www.runcolfax.org.