Event details subject to change. Please confirm all information via event website.
Dog Days of Summer 5K
Come join us on August 8, 2026 for a race around the entirety of beautiful Lake McIntosh! This 3.5 mile race is a half paved/half dirt course surrounded by wonderful mountain views, vast farmlands, and beautiful aquatic wildlife! Gather at Dawson Neighborhood park near the pirate ship playground where you will find an assortment of […]
Strides For Change
Join us on August 8th, 2025 at Sloan’s Lake for Strides for Change – a 5K for Youth Mental Health, presented by Resolute Counseling Center. This community-centered event is more than a race — it’s a movement to support and uplift the mental health of our youth. Hosted by Resolute Counseling Center, whose mission is to […]
St Vrain for the Brain 5K
Run or walk this charity 5k in which all proceeds benefit brain cancer research! There will be trophies for the top finishers in men, women, and youth. Costumes are encouraged — the best costume wins a prize!
Sarcoma Strong 5K
Hi all! Please join us at Sloan's Lake Park in Denver on 8/8 for a 5K to raise awareness for cancer! Specifically, sarcomas, a group of cancers that affect tissues such as bone and muscle. We hope to raise awareness for these often deadly, debilitating, and often overlooked cancers; for survivors, families, and the research/medical […]
HRCA Splash Mash Dash Kid’s Triathlon
Recreation Center at Northridge 8801 Broadway, Highlands Ranch, CO, United StatesThe Splash Mash Dash Kids Triathlon is the perfect for kiddos looking for a way to "TRI" the sport of triathlon or tune up their skills for a larger race. The race will offer kids a safe and fun environment for racing. To encourage participation and enjoyment for all, The Splash Mash Dash Kids Triathlon […]
Eat. Run. Adopt. 10K
Join us for Berthoud’s first-ever community-driven 10k! In partnership with Berthoud Pet Supply, this isn’t just a race—it’s a moving feast with a mission. A portion of race registration proceeds will go to Scroungy Dogs and Pretty Pups Rescue This community race and expo is designed to support Scroungy Dogs and Pretty Pups Rescue, a […]
Summer Sizzler 5K
Join us for the annual Summer Sizzler! Whether you are looking to run, walk or just enjoy the race SWAG this race is a sure thing for a great time and an incredible experience! This is a fun, family event for all ages with all distances!
Rocky Mountain Tri-Fest
Rocky Mountain Tri-Fest is Colorado's newest Multisport event, catering to the whole family. With events for everyone from mom and dad looking to try their hand at a gravel triathlon, to children looking to do their first triathlon. The Sprint and Super Sprint gravel Tris are beginner friendly with the bike course on the gravel […]
Pancake Stampede 5K
Hudson Gardens and Event Center 6115 S Santa Fe Dr, Littleton, CO, United StatesWork up an appetite for a deluxe breakfast at The Pancake Stampede 5K on August 15th! The race is a part of Littleton's Western Welcome Week celebration and held before the annual pancake breakfast at Geneva Park. The 5K takes place at Hudson Gardens.
Berkeley Circuit
Event Description Berkeley Circuit Race Schedule: 8:30- Free and Fun Kids Quarter Mile (no registration necessary, just show up to race!) 8:45- Community One Mile Run (all paces welcome- walkers, strollers, dogs!) 9:15- Competitive Waves Begin (10 person waves from slowest to fastest seed times) *All registered participants will receive a performance race tank with original […]
Into the Hills Eltuck 10K
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 […]
Canceled Gold Roots Trail Series #3
Courtney Ryley Cooper Park 2350 Colorado Blvd, Idaho Springs, CO, United StatesRun the Mighty ARGO hill this summer in a 4 race series! You will have the option of a short loop (~5 miles, ~750' gain) or a long loop (~9 miles, ~1400' gain). Both loops climb the Rosa Gulch trail and come down Virginia Canyon. Start and end in Courtney Ryley Cooper Park. Routes subject […]
Summit Trail Running Series V
Carter Park 500 South High Street, Breckenridge, CO, United StatesExplore the trails of Breckenridge this summer with the 23rd annual Summit Trail Running Series with each race followed by a post-race party! The Series consists of 5 trail races in and around Summit County, May-July. Each race features a short and long course, and all races are open to runners of all abilities ages […]
San Juan Softie 100
The softest 100 miler in the San Juans This 100 mile ultra marathon starts and finishes just north of Durango, Colorado. The race will take you through some of the most stunning and rugged terrain with breathtaking views of the Colorado Trail, Engineer Mountain, Wilson group of 14ers, Lizard Head, and many other incredible peaks […]
Weld County Commissioner’s Cup
This is a private event for Weld County employees and their families. The race is not open to the general public. Sorry!
Roxborough Ultras
Roxborough Ultras is a late-summer trail ultramarathon in Roxborough State Park, Colorado, offering a 50K and 50M on fully marked, all-trail courses. Both distances feature sustained climbing, technical sections, exposed terrain, and long stretches with little flat relief. The 50K includes over 5,000 feet of elevation gain. The 50M includes over 9,000 feet of elevation […]
Westminster Trail Race
Wayne Carle Middle School 10020 100th Ave, Westminster, CO, United StatesAfter a special night edition last year, Westminster returns to its traditional daytime format in 2026 — bringing runners back to a classic morning on the trails at Standley Lake.Now in its 12th year, Westminster Trail Race continues to be one of the Front Range’s most approachable and scenic trail events. The courses wind along […]
Mt Sneffels Half Marathon
The Mt. Sneffels Half-Marathon and Kids Fun Run began 25 years ago. In 2021, the 10 K was added. The Race is the foundation’s major fundraising event of the year. It is supported by sponsorships from businesses and individuals, over 400 race participants nationwide, 100 plus volunteers, and a dedicated race committee offering their time and […]
Boulder Rez Marathon
The Boulder Rez Marathon is quickly becoming a Boulder classic! This isn’t just another run around the lake. September temperatures will create the perfect race atmosphere. BBSC will offer a Marathon, ¾ Marathon, Half Marathon, 10K and relay, guaranteeing the perfect distance for you! This popular course will take runners around the Boulder Reservoir on […]
Cheyenne Mountain Run
The Cheyenne Mountain Run in Colorado Springs will take place on October 8, 2022 and will feature 3 trail races: a 25K to the top of Cheyenne Mountain for the more advanced trail runner, a 10K for the experienced runners and a 5K trail run for all to enjoy.
Med Bow Rail Marathon
The Friends of the Medicine Bow Rail Trail will host the second annual Med Bow Rail Marathon & Half Marathon on August 13th, 2022 at Lake Owen in the Medicine Bow National Forest near Laramie, Wyoming.
Dash for Democracy 5K
Dash for Democracy is the Denver Democrats' 5th Annual 5K Run / 2K Walk, taking place at City Park and bringing together community members for a morning of fitness, civic engagement, and fun. This election-year event is an opportunity to connect with neighbors, learn about candidates and issues on the ballot, and celebrate the importance […]
Frontier Academy Community 5K
The Frontier Academy Community 5K is meant to serve the community of Greeley and the surrounding area. Through this race we hope to fulfill the vision and mission of our school - 'Building Leaders'.
Dog Day 5K
Join us at Two Rivers Park in Glenwood Springs on Saturday, August 15 for a morning full of wagging tails, fresh air, and community spirit! The Dog Day 5K is a family and dog-friendly 5K race along the Rio Grande Trail benefitting the shelter pets of Colorado Animal Rescue (C.A.R.E.). Whether you're trotting alongside your pup […]
Sunrise Stampede 5K
The Sunrise Stampede 5K with a 1-mile fun run is a family-oriented run/walk that has raised $270,000+ for student programs in the St. Vrain Valley School District. All net proceeds support Teacher Innovation Grants for students with special needs. These grants are awarded to teachers who have innovative ideas to enhance learning for students. Help […]
Wild West Backyard Ultra
The MOCO Trails Wild West Backyard Ultra is a community-driven endurance event held at beautiful Loudy Simpson Park in Craig, Colorado along the banks of the Yampa River. This race follows the classic Backyard Ultra format where runners complete a 4.167 mile loop every hour, on the hour, until only one runner remains. If you […]
Miles for Migraine 5K
Miles for Migraine will host its annual 2-mile Walk (or Intentional Movement of your choice), 5K Run and Relax Denver Event. This event is a fundraiser for Migraine & Headache Awareness, Treatment & Research. It's more than a walk/run - come connect with your local migraine & headache community, listen to our speakers & visit sponsors […]
Just Peachy 5K
Join the Grand Junction Sports Commission for the Just Peachy 5K presented by Grand Valley Primary Care Palisade (Community Hospital) on Saturday, August 19th. This fun 5K is great for families and beginners, but also a very fast course for those looking to PR.
Grizzly 2 Mile
Every year TRXC hosts a race to begin the season and celebrate ThunderRidge High School Cross Country. This season we will be holding a Grizzly 2-mile on the ThunderRidge campus to get the season going! We are excited to give the community the opportunity to contribute to the program and race on campus. Please register […]
Buffalo Run 5K
Held during Grand Lake's iconic Buffalo Days weekend, the Buffalo Run 5k route passes through the charming town of Grand Lake, along the scenic shores of Colorado's highest and deepest natural lake, and past historic landmarks for one of the most unique races you'll ever experience! The race starts and ends at the Grand Lake […]
Please click here to submit your event for FREE to our online calendar.
We do not allow events without physical locations (IE – virtual runs, runs with locations TBD, etc…).
Please allow 48 hours after submission for an event to appear on the calendar. If you have already listed your event and would like us to update it, please contact us.