Event details subject to change. Please confirm all information via event website.
Mountain Swim Series IV
Highest altitude organized marathon swim event in the country at ~8,000 feet. RACE DETAILS Distance Price* Swimmers 2.5K $110.00 Both skin/wetsuit event options 1-hour swim cutoff** 1 loop around the course 5K $130.00 Both skin/wetsuit event options 2-hour swim cutoff** 2 loops around the course 10K $150.00 Highest altitude organized […]
Gunni Hi Tri
This Sprint Triathlon is proudly brought to you by the Gunnison Parks & Recreation Department. It begins with a 500yard swim (10 laps) at the Community & Aquatics Center, then continues with a 23K (14.5-mile) bike course, and wraps up with a 6.4K (4-mile) run that finishes at the Community Center. The kid's triathlon starts […]
Ram Run 5K
Come join in the celebration of the resurgence of a great community event. The Ram Run will be returning to it's traditional month. This fun and exciting event will include a 5k around the neighborhoods near Green Mountain High School. Proceeds will help benefit the Green Mountain High School Cross Country Team. The first 150 […]
Unite for Bleeding Disorders Walk
Sunlight Showdown 10K
Sunlight Mountain Resort 10901 County Road 117, Glenwood Springs, CO, United StatesWelcome to the Sunlight Mountain Race Series, where mountain air, winding trails, and a vibrant community come together for an unforgettable summer of running. For seven years, our half marathon has challenged and inspired runners on the stunning trails of Sunlight Mountain. Now, we’re taking it to the next level. Introducing a full race series: […]
Warrior Waterfront 5K
Come join us for the Warrior Waterfront 5k. This 5k will be run in conjunction with the Central High School Warrior Cross Country Invitational and all proceeds will go to support the CHS Cross Country Team. We are excited to run along the Las Colonias waterfront park area along with all of the activities available […]
Boulder 5K Taco Run
Super charge your Taco Crushing appetite with a run before the Boulder Taco Fest! A non-competitive fun run on some of Boulder’s most beautiful multi-use paths. There’s even an aid station with some Boulder Taco Fest-themed treats. You’ll finish up back at the Boulder Taco Fest, ready to celebrate your run at Boulder’s favorite summer […]
Pioneer Prairie Dog Half Marathon
Westminster Promenade 10600 Westminster Blvd, Westminster, CO, United StatesWelcome to the Pioneer Prairie Dog Half Marathon event; the one that started the series! With 10k and 5k events too! Everyone is back to school and slipping into a routine. Make this your mental health break as you break away from the chaos of weekly schedules and give yourself a morning to race in […]
Rebel Run 5K
Be part of something bigger at Conservation Colorado’s second annual Rebel Run 5K — where movement meets momentum for our climate, air, land, water and communities. Last year, more than 230 rebels showed up strong — rocking matching team shirts, rallying friends and family, and proving that protecting Colorado is a team sport. This year, we’re […]
Log Hill Hustle 5K/10K
Join us for the Annual Log Hill Hustle 5K & 10K, a scenic fun run/walk hosted by Fortuna Tierra Club in support of local education. Set against the stunning backdrop of the San Juan Mountains and Cimarron ranges, both courses begin and end at the beautiful Divide Ranch and Club, winding along gently rolling, fully […]
Central Park Kids Triathlon
Wellington Swim-Run Challenge
Swimmers may choose to swim with their shoes, paddles, a wetsuit, pull buoy, floaties, rubber duckies, inflatable flamingoes or any other nonmotorized swim aid in this event. Race Course Per Lap = 0.3 M Swim, 1.6 K Run Total: 3 Laps = 1 Mile Swim, 5K Run
PH in the Park
2026 marks 17 years of community, awareness, and fundraising to support people with pulmonary hypertension. The University of Colorado Denver, Children’s Hospital Colorado, and the Pulmonary Hypertension Association invite you to City Park in Denver for this annual 5K run/walk. Since our first event in 2008, this event has grown thanks to supporters like you. […]
Eltuck Valley 12K
Lory State Park 708 Lodgepole Dr, Bellvue, CO, United StatesJoin us each Tuesday evening in August for a fun series of shorter midweek trail races. Our goal is to offer a fun, low-key series of races designed to give newer trail runners an opportunity to dip their toes into the trail racing waters, and to offer more experienced trail racers a chance to sharpen […]
Continental Divide Trail Run
Steamboat Springs Ski Resort 2305 Mt Werner Cir, Steamboat Springs, CO, United StatesDistances: 50k (9 hour cutoff) and 16 mile (7 hour cutoff) and 5 mile (New!)
Rock Hawk Trail Race
Held on the gorgeous, thrilling and rolling trails of Castle Rock’s Miller Park & Ridgeline Trail systems. While not overly technical, these trails will challenge and excite, as you soak up the amazing views. This is an excellent race for both first-time and veteran trail runners, and provides a nice test for those who are […]
Boulder Sunset Triathlon
Summer may be coming to an end, but our tri season is still heating up! Join us at the Boulder Reservoir for the 13th Annual Boulder Sunset Triathlon, a local favorite. For the 5th year in a row we are the proud host of the Mountain Collegiate Conference race and the USAT Duathlon Race Series. […]
Waneka Classic Community 5K
A free, timed 5K, open to the public, held prior to the Centaurus Cross Country Invitational. Proceeds from the World Famous Concessions Stand and T-shirt sales benefit the Centaurus Cross Country Team. Stick around and watch Colorado's best student-athletes run the same course. A note about parking: Parking is available throughout the Waneka Lake residential […]
RexRun 5K for PAWSitivity
The RexRun 5K is a 5K run/walk to spread mental health awareness and #PAWSitivity in schools with the help of more Therapy K-9's like Arapahoe County Sheriff's Office K-9 Rex. This year's event is at Dove Valley Park in Centennial on August 6th.
Boulder Sunset 5K/10K
The Boulder Sunset 10K & 5K Run is part of BBSC’s biggest endurance event of the summer. Spend your weekend racing with BBSC at the incredible and scenic Boulder Reservoir. Register, and start training for the end-of-the-summer endurance festival with BBSC.
Thirsty 13 Half Marahton
It's a race. It's a Brewfest. It's the Thirsty 13 Half Marathon! Are you thirsty for gorgeous scenery? You won't find a course more beautiful than this one. With the majestic La Plata mountains in the background, you'll cruise through the lush pastures of Wildcat Canyon and past the pristine waters of Lake Nighthorse. This […]
Rocky Mountain 5K
In partnership with the YMCA Pikes Peak Region, we want to bring you the annual Rocky Mountain Run, the Rocky Mountain State Games official 5k! Athletes will be looped around Memorial Park starting at the IAFF Fallen Firefighters Memorial then head through the side streets of Memorial Park, around Prospect Lake, and finish back at […]
Historic Main Street 5K
Join us for this family-friendly event! The 5K run/walk will begin and end on Elizabeth’s historic Main Street, featuring a new and exciting course that crosses the reconstructed trail bridge and heads north into Evans Park, with a mix of pavement and dirt for varied terrain. The Family Color Run will take place in Running […]
Run Like The Wind 5K
Come race in the mountain town of Allenspark Colorado. Run the scenic 5K that circles through downtown and along dirt roads amid pine forest, boasting awe inspiring views of Mount Meeker and the Continental Divide. Enter your dog to run with you for an extra $5 and stick around for the post-race whimsical dog show. […]
Summit UP Run
We're bringing back our Summit UP Run presented by Mammut during Union Peak Festival weekend with spectacular views to jump-start your Saturday morning before relaxing and listening to music! Choose from a 5k or 5k Challenge route—both start & end at Aerie, located at the top of American Eagle lift. Celebrate your athletic pursuit at the Aerie […]
Ouray 50 Mile
A 50 That's More Difficult Than Your Last 100 How do you build a 50 miler that hits harder than most 100 milers? Easy. Start with a stout mountain hundred miler. Anything with ~24k feet of climbing should do. Find 50 miles of flat and discard it. Add copious amounts of highly-technical, unforgiving, why-would-they-even-think-this-is-a-good-idea trails. […]
Glow and Roll 5K
Glow & Roll is an inclusive, dusk-time 5K Walk/Run/Roll (with a 1.6-mile option). A glow-filled, twilight experience with lights, music and day-glow swag that transforms the event into a celebration under the evening sky. Movement in all forms is welcome whether you walk, run, use a wheelchair, or dance your way through the course. Creative […]
RMRR Fall Marathon Training Series #1
Riverwalk Ballfields 9830 Riverdale Rd, Thornton, CO, United StatesRMRR’s Marathon Training Series provides 10M and 20M races that are low cost, friendly, fully supported, and officially timed. All you need to do is focus on your running! Our races fit perfectly in training schedules for Colfax, Boston, New York, Chicago, and other full and half marathons. Everyone is welcome at our MTS races: RMRR members, […]
Bluffs 8K Trail Run
Prairie Sky Park 10249 Ridgegate Circle, Lone Tree, CO, United StatesThe Bluffs 8K Trail Race has rolling hills and beautiful views as you run or walk through the Bluffs Regional Park. The race will start/finish near the Prairie Sky parking lot o n August 28th.
Wine Run 5K
Join us on Sunday, August 30, 2026 for an exciting annual event that features the amazing scenery and landscape of The Winery At Holy Cross Abbey! Due to the huge turnout, we will have 2 start times for the event (9:30am and 11am). You'll select a start time when you sign up. Since July 2002, […]
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