The Denver-Boulder area has long been a hotbed for runners. Elite American distance runners began moving to Boulder in the 1970s to take advantage of the newly discovered competitive benefits of training at altitude. Elite foreign runners — including world record holders — soon followed. Then came competitive cyclists and other endurance athletes.
Coinciding with America’s first running boom, they were joined by countless recreational runners of all shapes, sizes, goals and race paces.
Five decades later, the Front Range racing scene continues to thrive. That the Bolder Boulder Memorial Day 10K was the third-largest road race in the U.S. last year, with 45,142 finishers — exceeded only by the New York City Marathon and the Chicago Marathon — speaks volumes about Colorado’s ongoing love affair with running and racing. It was an 8.8% increase over 2024, too.
“Isn’t that great?” said Bolder Boulder race director Cliff Bosley, whose father Steve co-founded the race in 1979 with Olympic marathon champion Frank Shorter. “Boulder is the epicenter of running, or one of them, in the country. I think it also speaks to the unique experience that the Bolder Boulder is, even 45 years after its founding.”
Here are five races you should strongly consider running in 2026, with some compelling reasons why we love them:
There is the beautiful setting at the foot of the Flatirons, the stadium finish at Folsom Field, costumes, water slides and live music along the 6.2-mile route. Because it’s Boulder, even the recreational runners post finish times unmatched elsewhere in American road racing. But there is also a solemn Memorial Day observance after the race. Many runners take part to honor friends and family members who gave the ultimate sacrifice for their country — or those currently serving in the armed forces — by wearing special bibs as tribute. After the race — taking place Monday, May 25 — thousands of runners remain in the stadium to witness ceremonies that honor fallen veterans and heroic veterans still living.
This event, which includes a half-marathon, 10-miler, half-marathon relay and a 5K in addition to the 26.2-mile title event, will mark its 20th edition the weekend of May 16-17. That’s driving a registration surge, according to chief executive Andrea Dowdy. “Registrations are going hog wild,” Dowdy said. “Everybody wants to run the anniversary years. We are seeing huge numbers.” Colfax saw 22,730 finishers last year, an increase of 6% over 2024. The half-marathon event has sold out several years in a row. All races begin and end in City Park.
Like the Bolder Boulder, the Georgetown-Idaho Springs half was founded in 1979 when running was just becoming a mass participation sport. Widely considered one of America’s most scenic half marathons, the race begins with a lap around scenic Georgetown Lake at 8,500 feet, then heads downhill on a gently rolling course to finish at 7,500 feet on historic Miner Street in the heart of Idaho Springs. Even though the race generally parallels Interstate 70, runners seldom notice the highway. It’s not only a beautiful run, but a peaceful one, too. This year’s race is scheduled for Aug. 8.
One of the area’s most popular running events, the races unfold on the scenic Platte River Trail. The half-marathon and relay begin at Reynolds Landing in Littleton and head north through Englewood and Sheridan to Denver before returning to the finish at Reynolds Landing with a post-race party at Breckenridge Brewery. The 5K distance is new this year. Race day is April 12.
: OK, the home team hasn’t won a lot in recent years, but everyone’s a winner in this 5K race, which includes a lap around the warning track inside Coors Field. Because it’s only 3.1 miles, it’s a great race for families with young children. This year’s date: May 9.
