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Rim to Rim Royal Gorge Races
Cross Americas highest suspension bridge over the gorge
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West Elk Challenge Trail Marathon
Point-to-point trail past Needle Rock into Gunnison forest
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The Loco Strikes Back: 9th Edition of the International Taco Bell 50k Ultramarathon
50K urban legend, run every International Taco Day
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Rut Run 5k
Fall colors and bugling elk along the Rut Run
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Sage Burner Trail Race
360-degree Rocky Mountain views over Hartman Rocks sagebrush
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The Bear Chase
Fast trail ultra around scenic Bear Creek Lake Park
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Wildcat Mountain Trail Races
Trail winds through HRCA's Backcountry Wilderness Area
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Colorado Springs Marathon
Four race distances in the heart of Colorado Springs
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Above the Clouds Ultra
Singletrack round Rampart Reservoir, Pikes Peak views
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The Pretzel Run
10k runs a flat loop, 5k runs a hillier loop
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Miles for Moms Run/Walk/Roll
A Denver mile through Huston Lake Park for teen moms
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October Trophy Series
Handicap starts on Aurora's Sand Creek Trail
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Windsor Marathon, Half Marathon, 10k, 5k & 1 Mile Run
Colorado's run.Windsor Race Series marathon
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Des Plaines River Trail Races
Flat crushed-gravel trail race through forests and wetlands
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Long View Marathon and Half Marathon
Point-to-point marathon linking Fort Collins and Loveland
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Manitou 5K
Loops Manitou Springs' murals, parks and Creekwalk
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Breckenridge RunFest
High-altitude marathon at 9,600 feet in the Rockies
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Durango Marathon
Rocky Mountain marathon along the Animas River valley
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Westy Half & 5k
Follows the Big Dry Creek Trail in a bow-tie route
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The Great Trailhead Foot Race 5 & 10 Miler
Singletrack in the shadow of Denver's skyline
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Blue Sky Marathon & Half
A trail marathon over Colorado Front Range hogback ridges
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Indian Creek Trail Runs
Front Range single-track through pine forests and red rock terrain
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Bobcat Trail Races
City park trails with rocky bluff views of Pikes Peak
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4TH ANNUAL HALLOWEEN HUSTLE FOR CHARITY
In a mountain valley where two rivers meet
Save any of these to your season in RunCalendar and hear the morning entries open. Free on iPhone, no account needed.
Every race here is published by its organiser; RunCalendar checks the date and the entry window against the organiser's own page and rebuilds this calendar every night. A confirmed date shows its day; a provisional one shows only its month. Last updated 22 October 2026.