2026 Denver Colfax Marathon
The 2026 Denver Colfax Marathon is scheduled for May 17, 2026, in Denver, Colorado. Participants will navigate the urban terrain of America's longest main street, experiencing an elevation ranging from 5,180 to 5,480 feet. Typical weather in Denver during mid-May includes mild to warm temperatures, though runners should prepare for the physiological effects of high altitude and potential mountain weather fluctuations. This large-scale running weekend features multiple race distances and a two-day Health & Fitness Expo held prior to the main event.
What races are offered at the Denver Colfax Marathon?
- →Marathon (26.2 miles)
- →Half Marathon (13.1 miles)
- →Urban 10 Miler
- →5K
- →Marathon Relay (featuring over 1,100 teams)
What is the course layout for the Marathon?
The USATF-certified marathon course is an out-and-back route starting from Ferril Lake in City Park and heading west to Lakewood. Detailed information can be found at Runcolfax ↗. The course is divided into five distinct sections:
- →Urban River: Includes a stadium run-through at Empower Field and Fire Station #1.
- →No Groans at Sloan's: Features views of Sloan's Lake.
- →Eclectic Mile High: Passes Casa Bonita and an art campus.
- →Screaming Downhill: A fast return via Colfax Avenue.
- →Downtown River Trek: A second stadium loop from 16th Street Mall to the City Park finish.
What can runners expect on the Half Marathon course?
The Half Marathon focuses on an eastward route starting in City Park. You can view the course overview at Runcolfax ↗. Highlights include:
- →The Zoo Mile, which takes runners past rhinos and elephants through the Denver Zoo.
- →Montview Blvd and the eclectic landmarks of Colfax, such as VooDoo Donuts.
- →A unique run through the Cathedral Basilica, the Capitol, and Fire Station.
- →A finish through the Convention Center, 16th Street Mall, and 17th Avenue restaurants back to City Park.
What are the details for the Urban 10 Miler?
The Urban 10 Miler covers the final 10 miles of the full marathon course. Specific course details are available at Runcolfax ↗.
- →The route includes the Empower Field stadium run-through, downtown, Confluence/Cherry Creek trails, 17th Avenue, and a finish in City Park.
- →The race features a staggered start from RMCAD, where runners eventually merge into the marathon course.
- →Participants receive RTD transit to assist with travel back from the course.
What should runners know about the terrain and altitude?
- →The races are held on closed city streets with urban terrain.
- →Elevations range between 5,180 and 5,480 feet.
- →The course includes moderate hills, but the marathon features a net downhill return which is conducive to personal records (PRs).
- →Participants should plan for altitude effects due to the Rocky Mountain location.
Are there any other events held during this weekend?
- →A two-day Health & Fitness Expo is held before the races.
- →The Colorado Running Hall of Fame inductions are part of the weekend festivities.