The Ralston Creek Half Marathon and 5K are back in 2025 and we are excited to announce the Racing Underground Winter Running Series also returns in 2025! Join us at Colorado's Premier Winter 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 covers 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 2.5 hours to complete the course!

Schedule:

7:30 a.m. - Packet Pick-Up Opens
9:00 a.m. - Wave-1 Start (half-marathon runners expecting to be on the course longer than 2 hours 45 minutes)
9:45 a.m. - Wave-2 Start (half-marathon runners expecting to take less than 2 hours 45 minutes)
10:00 a.m. - Wave-3 Start (all 5K runners)
10:45 a.m. - 5K Awards Presentation*
11:30 - Half-Marathon Top-3 Overall Awards Presentation*
1:30pm - Finish Line Cutoff

Course Info:

Half-Marathon:

The Ralston Creek Half Marathon course follows a mix of roads and bike paths on the west side of Arvada. The opening 5 miles are fairly flat, with a barely noticeable gradual gain in elevation. Miles 5 through 6.5 are rolling, with one good climb leading to the high-point of the course atop Ralston Mesa at 7.75 miles. From there, the course is almost all downhill and flat to the finish, with the exception of a small bump around mile 9 and a very gradual uphill in the last half-mile.

Click Here for a Half-Marathon Course Map

5K:

The Ralston Creek 5K Run course follows a mix of roads and bike paths on the west side of Arvada. The route starts with a slight downhill in the opening mile, a flat second mile, and a very gradual uphill in the final mile. A single aid station will be located at approximately halfway into the 5K run.

Click Here for a 5K Course Map

Awards:

The top-3 male and female finishers in the half-marathon will take home cash awards in the amount of $100, $75, and $50. The top-3 male and female 5K runners will receive merchandise or gift certificate awards. Overall winners will be determined by gun time (first three across the finish line are our top-3) and will excluded from age group awards.

Awards will also be presented to the top-3 finishers in each age group in both the 5k and the half marathon. Age group placing is determined by net time (each runners time starts when they cross the start mat and ends with they cross the finish mat). 5k Age Groups are 12 & under, 13-19, then 5-year age groups from 20-24 through 85-89, and 90+. Half Marathon Age Groups are 19 & under, then 5-year age groups from 20-24 through 85-89, and 90+. We have also added a non-binary award category to the 5k and half marathon. The top-3 overall non-binary finishers in each distance will take home an award.

Cost:

5K Run

$35 from Oct. 16 - Dec. 31
$40 from Jan. 1 - Feb. 6
$45 from Feb. 7 - Feb. 15
Youth age 12 & under pay just $25 pre-reg. for the 5K
RACE DAY REGISTRATION: $50

Half Marathon

$75 from Nov. 1 - Dec. 31
$80 from Jan. 1 - Feb. 6
$85 from Feb. 7 - Feb. 15
RACE DAY REGISTRATION: $95

Click here to Register