Event details subject to change. Please confirm all information via event website.
Ralston Creek Half Marathon
Move by Morelli 6542 Fig Street, Arvada, CO, United StatesThe 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 […]
Chilly Cheeks Winter Duathlon
Cherry Creek State Park 4201 S Parker Rd, Aurora, CO, United StatesThe Chilly Cheeks Duathlon Series is now a stand-alone event held in late February. The 63rd Chilly Cheeks Duathlon will be held in the traditional format of Run-Bike-Run. Both runs will be 2.5 miles in length and the bike course will be an 11 mile paved road route. As always, we will provide a marked […]
Three Creeks Half Marathon
Racing Underground brings you an amazing half marathon this spring! The Three Creeks Half Marathon features a half marathon course that is flat, fast and scenic! Travel on foot through some of the most beautiful parts of Cherry Creek State Park, with a total combined elevation gain of only 291 feet spread out over 13.1 […]
Donut Dash
The Donut Dash 5K is Denver’s race that ends with doughnuts. Runners and walkers can take advantage of a flat and fast course, and then enjoy fresh doughnuts at the finish. Our mission is to bring people together to have a fun, fit morning.
Platte River Half Marathon
Denver's oldest half marathon runs along the Platte River Trail, covering parts of Littleton and Denver.
Rattler Trail Race
Rattler was created to feature one of Colorado Springs' best city parks, Palmer Park. Runners will enjoy views of the city and Pikes Peak from the sandstone bluffs, while running all of the best trails the park has to offer! Even though the course does not have much vertical gain, it will test runners with […]
Greenland Trail Race
The Greenland Trail Race offers four outstanding distances in southern Douglas County. Run the 4 Miler, the 8 Miler, the 25K, or tackle the 50K ultramarathon, Colorado’s fastest 50K! With Pikes Peak as your backdrop, you’ll cruise over a soft dirt trail on your way to a new personal best. With chip timing, an innovative technical running shirt in men’s and women’s sizing, food and beer at the finish, this race will make you want to come back for more!
Colorado Marathon
Marathon, Half Marathon, 10k, 5k and 3-Person Marathon Relay. Marathon, Marathon Relay and Half Marathon runners get to run down the scenic, downhill Poudre Canyon to the finish in Old Town, Fort Collins, where we have live music and a big post-race party featuring beer from Odell Brewing Company. For 2027 Boston Marathon qualifiers, races […]
Wine Run 5K
Like Running or Walking? Love Wine? This race is for you! Join us on Saturday, May 8, 2027 at 9:30am and 11:00am (you will pick your start time during registration) for an exciting annual event that features the amazing scenery and landscape of Colterris Winery! With over 75 acres of vineyards, Colterris is Colorado’s largest […]
PPRR Nielson Challenge
North Monument Valley Park 1794 Culebra Ave., Colorado Springs, CO, United StatesRace Format The first time you run this event, you'll establish a base time for yourself. This base time is used to generate a handicap time. The handicap time is calculated using an algorithm developed by Bob Royse, and it's geared to favor a beginning runner and the slower runners. Click here for an explanation of the […]
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