Trail Running calendar near Longmont 2026-2027

Trail races at Greenland Open Space in Larkspur, Colorado offer 4 mile, 8 mile, 25K and 50K distances on dirt double-track trails with aid stations and championship designation for the 50K.

Niwot's Challenge is an invitation-only navigational ultrarunning trial near Sedalia, Colorado. Entrants must use map and compass, carry mandatory gear, and complete long off trail loops with minimal aid.

Experience the 45th annual run along the scenic High Line Canal in Centennial. Enjoy chip timed 5K or 10K races followed by a pancake breakfast and beer garden.

Join the Aurora community for an untimed 1k fun run or a timed 5k race ending with an optional muddy obstacle course. This rain or shine event welcomes runners and walkers of all ages.

Experience the rugged beauty of the Rocky Mountain foothills in Fort Collins with a 25 or 50 mile trail race through Lory State Park and Horsetooth Mountain Park featuring significant vertical gain and scenic ridgeline views.

A community trail event in Kittredge, Colorado featuring a 7.4 mile route through local trails and a kids run based on one 0.15 mile lap per year of age. The race is manually timed and includes post race food and activities.

Samson's Revenge is a trail race at the YMCA of the Rockies in Estes Park offering 50k, 25k and 10k options. The course uses a roughly 10 km loop with a prominent Bible Point ascent and two aid stations.

Test your endurance at this Golden Colorado event following the classic backyard format with 4.17 mile laps every hour. Support the Sun Valley Kitchen and Community Center while pushing for your personal best distance.

A weekend running festival in Eaton, Colorado offering distances from 7K to 100 miles, relay teams and 36 hour options on a 2 mile groomed dirt loop, with on-site camping, glamping and amenities such as sauna, cold plunge and aid stations.

Trail ultramarathon near Buffalo Creek, Colorado offering 50 mile and 50K on soft surface singletrack with short double track sections. Part of the proceeds support the North Fork Volunteer Fire Department.

A 5k trail race through the rolling hills of Elk Meadow Park in Evergreen, Colorado, with vendor tents, rec trailer activities and refreshments. The course is cup free and has no aid stations, with marshals on course.

A Parker, CO trail event with a Dipsea style staggered start, a rolling, partly technical 10k and a kids 1 mile. No race day registration; volunteers may race for free and a top-10 podium and awards are given.

Six trail races across Summit County, Colorado, in summer 2026. Series registration includes long and short course options with adult, youth, and non binary categories and events at multiple Summit County trail heads.

Trail races at Granby Ranch Resort in Colorado offer multiple distances including a 14 hour Elevation Challenge based on completed loops. The combined field is capped at 250 and the event includes aid stations, drop bag options, and on-site..

A multi-distance running festival at Luvin Arms Animal Sanctuary in Erie, CO, featuring looped off-road courses with mountain views, one central aid station, onsite parking, and races from 5k up to 50 miles plus 3hr/6hr/9hr/12hr timed event..

A looped 10k plus trail run at Devils Backbone Open Space in Loveland featuring marked singletrack, an aid station near mile three served twice, old school timing with a finish stick, and an awards gathering at Loveland Aleworks.

A high altitude trail 10K on Vail Mountain with sustained elevation change and varied terrain, a mass start shared with the 20K, cupless aid stations with a provided collapsible cup, and a total prize purse of $12,200.

A four race trail series at the Argo trails in Idaho Springs, Colorado, held June to September 2026. Each event is about 5 miles with 785 feet of gain on non technical, runnable trails with visual finish timing.

Looped trail races at Barr Lake State Park in Brighton Colorado offer 50K, 30K, half marathon, 15K and 5K options on dirt surfaces with lake and Front Range views. Aid station coverage varies by distance.

Experience up to three miles of messy fun at the Colorado National Speedway. Navigate obstacles by crawling wading and sliding through the mud with friends and family during this unique event in Dacono.