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DENVER (KDVR) — The Denver Colfax Marathon is returning this weekend for the first major race in Denver since 2019. Traditionally the race is held in May, but COVID concerns moved the races to Saturday and Sunday.

Early Saturday morning, participants will make their way to City Park for the start of the 15th Denver Colfax Marathon.

“We are excited to celebrate our 15th year by having a robust week of events throughout the city, and to announce a brand new half marathon course,” said Andrea Dowdy, CEO of Denver Colfax Marathon. “The new course enables half marathoners to enjoy downtown and part of the marathon course but keeps the great one-mile trek in Denver Zoo. This change is also great for spectators, who will be able to watch runners in all race distances at points during the course.”

About 14,000 runners will descend on Denver for Saturday’s race. It’s a 26.2-mile run that goes up and down what is often touted as America’s main street.

In addition to the full-length marathon, the Urban 10-miler, Marathon Relay and Half Marathon runs take place on Saturday. The 5K run will be on Sunday.

The race goes up and down a major road, so traffic could be an issue Saturday and Sunday mornings. Drivers should prepare for road closures and delays along the race route. Check traffic closures here.

RTD is accepting Colfax Marathon 2021 race bibs as valid fare payment on Saturday. The following rail line and bus routes will accept the bibs:

  • Rail line: W Line
  • Bus routes: 15, 15L, 16

RTD says light rail and bus routes will experience temporary detours. The RTD website has up-to-date information at plan a trip.

D, H and L light rail (Saturday only):

  • D and H Lines will not serve Colfax at Auraria Station through the downtown loop
  • D and H Lines will continue to serve 10th•Osage Station, and will detour to serve Auraria West Station, Empower Field at Mile High Station, Ball Arena•Elitch Gardens Station and Union Station
  • The L Line will not be in service, and customers are encouraged to use bus Route 43 as an alternative option
  • Customers looking to connect to downtown can take the Free MallRide to/from Union Station
  • No impacts to RTD rail service are expected to occur on Sunday, Oct. 17

Bus routes:

  • Oct. 16 only:  the following bus routes will be temporarily detoured in many areas, and will be allowed to cross the marathon route when possible: 0, 1, 6, 8, 9, 10, 12, 15, 15L, 16, 19, 20, 24, 28, 30, 38, 43, 44, 48, 51, 52, 76, 83L
  • Oct. 17 only:  routes 20 and 24 will also have a minor detour around the event from 9 to 11 a.m. during the Colfax 5K race