The Ralston Creek races feature a fun winter half-marathon and 5K run conveniently located on the west side of the Denver Metro Area in Arvada, Colorado. The courses cover a scenic mix of road and bike path over rolling terrain, and an optional early start time for half-marathon runners who expect to take more than 2 hours 45 minutes to complete the course!

Half-Marathon entry is limited to the first 650 registrations. 5K registration is limited to the first 350 entries. Once a distance has filled, we cannot accept any additional entries for that distance.

Your entry fee includes entry into the race, a finisher's medal (for half-marathon runners who complete the course), FREE race photo downloads, fun music, hot cocoa and tasty quesadillas fresh off the grill!!!

Long sleeve adult tech shirts will be included with all half marathon entries. 5k entries will come with a short sleeve t-shirt or an upgrade to a long sleeve tech shirt for $5.

The post-race festivities will continue at the nearby Colorado Tap House located just above our 2 & 11 mile aid station on Ralston Creek trail (14982 W.69th Ave by car) where you can show you race bib any time on race day and receive $2 off a beverage item of your choice.  With 30 taps there are plenty of beer options, but also cider, seltzer, wine and cocktails.  They serve coffee drinks, kombucha, CBD Cider, Tommyknocker N/A Beer, Root Beer and soft drinks.   They also serve small food items and the food truck of the day rolls up at noon! 

This is also the final race in the Racing Underground Winter Running Series.  The three-race series includes the Stocking Run 5K in December, the Yeti Chase 5K/10K in January, and the Ralston Creek Half-Marathon & 5K in February. Choose from the 5K-5K-5K series or the 5K-10K-Half Marathon Series.

WINTER RUNNING SERIES

Series Finisher Awards to all runners who finish all three series races, and Overall Awards to the top series finisher in each age category!

December 13, 2025: Superior Stocking Run 5K (Superior, Colorado)

January 25, 2026: Yeti Chase 5K/10K (Lakewood, Colorado)

February 15, 2026: Ralston Creek Half Marathon & 5K (Arvada, Colorado)