Ralston Creek Half Marathon & 5k - Half Marathon

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. 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 12, 2026: Superior Stocking Run 5K (Superior, Colorado) January 24, 2027: Yeti Chase 5K/10K (Lakewood, Colorado) February 14, 2027: Ralston Creek Half Marathon & 5K (Arvada, Colorado)