Check out these Colorado 5Ks near you + some triathlons, marathons and ultra marathons too

Jan. 4, 2025
Participants of the 2024 BOLDERBoulder in Boulder, Colorado. Photo by Brooks Upham, courtesy of BOLDERBoulder.
Participants of the 2024 BOLDERBoulder in Boulder, Colorado. Photo by Brooks Upham, courtesy of BOLDERBoulder.

The BOLDERBoulder is a Colorado classic which takes place every year on Memorial Day and draws runners from all over.  Whether you’re gearing up for a summer of running or looking to stay active throughout the year, this guide has you covered.

Check out these tips and race calendars for Colorado 5Ks near you. And for more advanced runners, this guide goes well beyond 5Ks. Many of these races offer various distance options, so a half marathon may include 5K and 10K distances as well, and nearly all marathons have half-marathon options.

We classified these races based on the most interesting distance for each event. So if you don’t immediately see a 5K option for a race you want to try, look again. There are many additional 5K options tucked inside other races.

5Ks to try running during the summer in Colorado

Fourth of July running races in Colorado

Summer 5Ks that take place before and after July 4

  • Colorado Rockies Home Run 5K — This race gives you the chance to run a lap around Coors Field in addition to downtown Denver. At least someone will touch home plate this year besides Rockies’ opponents.
  • Sierra’s Race — This longtime Loveland race honors Sierra Krizman, who died of meningitis at age 20, and raises money for the fight against the disease that killed her.
  • The Summer Scamper 5K for All — The Scamper is an all-ability race that encourages people to get outside and enjoy nature. The Scamper takes place at Denver’s James A. Bible Park and supports the High Line Canal Conservancy’s work to preserve, protect and enhance the historic 71-mile High Line Canal. The Scamper includes a children’s Ditch Dash along with a 5K and a festival.
  • Pirates Run for Booty — Grab a coin at the finish of this race in Thornton. Some coins are worth prizes. Some are race vouchers — because everyone loves more running as a reward for running — but some are worth cash up to $100.
  • The Rocky Mountain 5K — This is the official 5K of the Rocky Mountain State Games in Colorado Springs and includes a downtown summer festival, a free Sasquatch Shuffle for kids and a dog bandana for pooches.
  • Dash for Smiles — This Denver race has raised more than $140,000 for local cleft pallet clinics.
  • Sunrise Stampede — This Longmont race is in its 39th year and supports mental health teacher innovation grants and special education.
    The "Into The Wild" running Festival has three events you can choose from: a 5K family fun walk/run or competitive 5K or 10K races. The event takes place about 30 miles from Denver and benefits The Wild Animal Sanctuary nearby. Photo courtesy of The Wild Animal Sanctuary.
    The “Into The Wild” running Festival has three events you can choose from: a 5K family fun walk/run or competitive 5K or 10K races. The event takes place about 30 miles from Denver and benefits The Wild Animal Sanctuary nearby. Photo courtesy of The Wild Animal Sanctuary.

10Ks — This is a hard distance to find beyond the BOLDERBoulder, but there are several good ones available in Colorado, and most have 5K options.

  • Into the Wild running festival — This race offers a chance to run through the beautiful plains of Keenesburg and the Wild Animal Sanctuary, where you can see rescued animals such as bears and tigers and a free opportunity to tour the place after the race.
  • Father’s Day Classic — If you’re feeling ambitious, there’s a 10-miler, too. This Arvada tradition includes a free car show.
  • The 80s run — A rare evening race at 5 p.m. and a free concert at 7 p.m. by That 80s Band, which features your favorite hip-hop classics from the 2000s (we’re joking), in addition to a plastic cup, big hair and breakdancing contests and an iron-on T-shirt. It takes place in Littleton.
  • Boulder Sunrise Run — Celebrate the Summer Solstice around the Boulder Reservoir.
  • The Deja Vu 10K — This Brighton race offers a funny name (because you just loop the 5K course again) as well as twice the distance for just $10 more, which we think is a pretty good deal.
  • The Dynafit 10K at 10,000 feet — if you don’t think a 10K is challenging enough, why not do it in much thinner air? This takes place in Vail.
  • The Human Race and Mountain Avenue Mile — Two iconic Fort Collins races in one weekend. The Mountain Avenue Mile takes place Friday night, and if you think a mile is easy, try running it as hard as many of the competitors. A 10K is the best way to run the Human Race, but it also offers a half marathon and a 5K.
    Participants take off during the annual Boulder Sunrise Run in Boulder, Colorado, which offers a 5K and 10K course. Courtesy of BBSC Endurance Sports.
    Participants take off during the annual Boulder Sunrise Run in Boulder, Colorado, which offers 5K or 10K courses. Courtesy of BBSC Endurance Sports.

Half Marathons

  • Slacker Half Marathon — This course is terrific both because it’s gorgeous and it’s a fast downhill just begging you to get a PR. It takes place at the base of the Loveland Ski Area into Georgetown.
  • All Out Dog Days — A race to benefit second-chance pooches in Westminster and a chance to see what your dog can do as well as you. The fastest dogs get a prize.
  • The Rocky Mountain Half — This race runs near the perimeter of Rocky Mountain National Park in a fun tourist town, Estes Park.
  • Georgetown to Idaho Springs — The unofficial second half of the Slacker, this race is also fast and scenic.
  • The Labor Day Half Marathon — This race in Parker gives you a chance to run off the backyard grilling treats that are a staple of Labor Day.
    Participants in the 2024 BOLDERBoulder enjoy bubbles, blue skies and a beautiful course at the classic Memorial Day race in Boulder, Colorado. Photo by Brooks Upham, courtesy of BOLDERBoulder.
    Participants in the 2024 BOLDERBoulder enjoy bubbles, blue skies and a beautiful course at the classic Memorial Day race in Boulder, Colorado. Photo by Brooks Upham, courtesy of BOLDERBoulder.

Trail runs — If you’re a dirt diva, Colorado has as many trail races as anywhere in the country.

  • Elk Meadow Trail Race — The Town of Evergreen presents a run through the rolling hills of Elk Meadow Open Space Park. This race is one of four the town hosts that are suited well for beginner or intermediate trail runners throughout the summer.
  • Sunset Trail Running Festival — Choose between a 28K, a 12K or 5K that start and finish on Main Street in Gold Hill and run on U.S. Forest Service roads.
  • The Barr Lake 30K and 15K — A flat and fast course, especially for a trail race, around a gorgeous state park in Brighton known for birding.
  • Spring Creek Memorial Trail Run — A 9.5-mile race on a primitive trail through Steamboat Springs that honors Patty Brenner Hagberg, who was struck and killed by a truck along the lower part of the trail in 1991. This race is part of the Steamboat Springs Trail Running Series.
  • Holy COW Trail Stampede — A Westminster race that offers a 10K or 5K.
  • Run the Rockies Trail Race — This 5K, 10K or half marathon race leads runners through the Frisco Peninsula trails with views of Lake Dillion and the Tenmile mountain range.
  • Westminster Trail Race — There are many trail races perfect for beginners, and this race is a great example, a dirt, non-technical trail around a beautiful lake, with 5K, 10K and half-marathon options.
  • Black Squirrel Half Marathon — This difficult race through Lory State Park is part of the fantastic Gnar Runners trail series with many challenging races in Northern Colorado.
    Runners of all ages (and babies in strollers) enjoy a 5K in Old Town Fort Collins, Colorado. Photo courtesy of the City of Fort Collins.
    Runners of all ages (and babies in strollers) enjoy a 5K in Old Town Fort Collins, Colorado. Photo courtesy of the City of Fort Collins.

Marathons — We don’t have many marathons in Colorado during the summer. They tend to take place in the fall, when it’s cooler, unless they are at higher elevations.

  • Estes Park Marathon — Billed as one of the most scenic road marathons in the U.S., Forbes Magazine rates it as one of the top seven in the U.S.
  • The Leadville Trail Marathon and Heavy Half — This race takes place in the iconic running town of Leadville. If you’re dying for a chance to run the highest and self-described hardest marathon in the country, this is your race. It can sell out and then you’ll be put on a waiting list.
  • Aspen Valley Marathon — See beautiful Aspen from your shoes.
  • Boulder Rez Marathon — If you don’t mind the heat, you can run this scenic, four-lap course around the Boulder Reservoir.
  • The Fall Equinox — Enjoy the wild scenery of the Poudre River all the way down the canyon near Fort Collins, a perfect chance to PR both because of the downhill course and the cooler September weather.

Ultramarathons — Colorado is packed full of ultramarathons, which is great for when 26.2 miles just isn’t enough to quench your thirst for a solid summer race.

  • 12-hour Last Man Standing Event — This race follows the Big’s Backyard Ultra format, which is something kids would dream up, if they were sadists. Competitors run 4.1 miles every hour until they stop or, if you’re hardy, for the entire 12 hours. It takes place in Windsor.
  • Chase the Moon 12-hour endurance run — This one isn’t quite as Game of Thrones as other Colorado ultras, as you’ll get the chance to run all night through foothills on the Highlands Ranch Backcountry trail system, and you can run as much as you want. There’s also a 50K option. It’s part of the Aravaipa Running series, and you can join up with friends or family if you don’t want to run the entire 12 hours yourself.
  • Sheep Mountain Ultras — A 50K, 50-miler or measly half marathon in Fairplay, nearly all of it above 10,000 feet. The race is part of the challenging but excellent Human Potential running series.
  • Leadville 100 — Many of the more famous and difficult ultras in Colorado are also difficult to get into, and this masterpiece is no exception. But it’s a fun race to watch, if you can control your FOMO, or even help crew or pace a runner.

Triathlons — We know some of you prefer to swim, bike AND run, so here’s some races for you freaks as well. Most offer Olympic and Sprint distances.

  • Loveland Lake to Lake — This classic race takes place in Loveland.
  • Boulder Peak — Another classic, this one takes place around the reservoir in Boulder.
  • Steamboat Lake — A chance to race in Steamboat.
  • Harvest Moon — This race offers a half Ironman-distance tri, where you swim 1.2 miles, bike 56 and run a half marathon, in Boulder. Whew.
    Unique outfits are part of the fun at the classic race that launches summer running races in Colorado, the BOLDERBoulder. Participants enjoyed a beautiful day for the 2024 race in Boulder, Colorado. Photo by Brooks Upham, courtesy of BOLDERBoulder.
    Unique outfits are part of the fun at the classic race that launches summer running races in Colorado, the BOLDERBoulder. Participants enjoyed a beautiful day for the 2024 race in Boulder, Colorado. Photo by Brooks Upham, courtesy of BOLDERBoulder.

Obstacle Races — You might as well throw some barbed wire, rope climbing and lots of mud into a race, right? Many of these obstacle races are now defunct, but these two stalwarts remain.

  • The Spartan — The OG offers more than a dozen obstacles into a 5K, 10K, 21K or, gulp, 50K (with 60 obstacles) in Colorado Springs.
  • Tough Mudder — A 5K, 15K or eight-hour infinity course in Fort Carson.

Bonus. What’s the other holiday that inspires 5Ks in Colorado?

For those of you who like to solve riddles, the other holiday that’s popular for 5Ks is an especially good day to get some exercise before you eat a giant meal. It’s Thanksgiving, of course, when you can enjoy a turkey trot before your turkey feast.

About the author

Dan England has worked for Colorado media for 25 years, including 20 at the Greeley Tribune. He's won more than 100 state and national awards, including Best of Show from the Colorado Press Association in 2015. Dan loves to write about the outdoors, as they are not just a job but an adventure. He has completed more than 20 marathons and 20 ultramarathons in addition to climbing more than 200 peaks, including all the 14ers in Colorado and Mount Rainier in Washington. He is a running coach, specializing in ultramarathons, and is certified by the UESCA. Dan is married to Valerie Vampola, a professional singer, and has three children, Jayden and twin girls, Andie and Allie, and a heeler, Pepper, who ran her first trail marathon last year in western Kansas.