Running races in Colorado in May 2027

32 races in date order

Greenland Trail Races
Sat 1 May 2027 · Elbert, CO · 50K · 25K · 8 Mile · 4 Mile
Rolling oak hills with views of Pikes Peak

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Take 5 in the Garden of the Gods
Sat 1 May 2027 · Colorado Springs, CO · 15.3 km · 5 Mile Road Race · 5 Mile Trail Race · 5K
A closed-road race amid Garden of the Gods red rock formations

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Duck Waddle 5K
May 2027 · Estes Park, CO · 5K

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Longmont Half & 5k (LM Half)
Sun 2 May 2027 · Longmont, CO · Half Marathon · 5K
Longmont's only half marathon

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Colorado Marathon
Sun 2 May 2027 · Fort Collins, CO · Full Marathon · Half Marathon · 10k · 5K
One of Colorados fastest downhill marathons through Poudre Canyon

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Collegiate Peaks Trail Run
May 2027 · Buena Vista, CO · Marathon · Half Marathon · 10K · 5K
A premier Rocky Mountain trail run with stunning alpine vistas

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Dash & Dine 5k Race Series
Tue 4 May 2027 · Boulder, CO · 5K

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HRCA Mother's Day 5K
May 2027 · Highlands Ranch, CO · 5K

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Run to the Shrine
May 2027 · Colorado Springs, CO · 4-Mile Run/Walk
Climbs 1,000 feet to the Will Rogers Shrine

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Quad Rock 50/25 Mile
May 2027 · Bellvue, CO · Quad Rock 50 Mile · Quad Rock 25 Mile
A trail ultra through Lory State Park with Rocky Mountain views

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Adventure Fest
May 2027 · Fruita, CO · 22.2 km
Trail half marathon on Fruita's desert singletrack

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Science Stride 5k
May 2027 · Boulder, CO · 5k

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Valkyrie Trail Race
Sat 8 May 2027 · Colorado Springs, CO · 50K · Marathon · 30K · Half Marathon · 8 Mile · 4 Mile
Loops climbing Cheyenne Mountain's singletrack

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Carbon Valley Half Marathon
Sat 8 May 2027 · Firestone, CO · Half Marathon · 5K
Rockies views crown a two-mile downhill fast finish

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Denver Mother's Day 5K
Sun 9 May 2027 · Denver, CO · 5K
Loops through Denver's City Park on Mother's Day

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Miles over the Meadow Mother's Day 5K & Family Fun Trek
May 2027 · Parker, CO · 5K · Family Fun Trek

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Colterris Wine Run 5k
May 2027 · Palisade, CO · 5K
Loops through Colorado's largest estate winery

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Colorado Women's Classic - Westminster
Sun 9 May 2027 · Westminster, CO · 10 Miler · 10K · 5K · Kids Fun Run

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Ram Party Trail Runs
Sat 15 May 2027 · Colorado Springs, CO · 55 Mile · 60K · 50K · 24K · 15K
Trail miles above Rampart Reservoir, Pikes Peak views

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Boneyard Boogie 14K & 6K
May 2027 · Eagle, CO · 14K · 6K
14K through Eagle's pinyon and juniper singletrack

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Vallecito Lake Heavy Half
Sat 15 May 2027 · Bayfield, CO · Heavy Half
A rugged half marathon beside Vallecito Lake

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Memorial Day March
May 2027 · Colorado Springs, CO · 30K Ruck · 10K · 5K

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Endure Trail Runs
Sat 15 May 2027 · Florissant, CO · Marathon · Half Marathon · 10K
Colored balls decide your loop at this 12-hour trail run

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Miles for Smiles 5K Run / Walk & Jordyn's Adaptive Dash
May 2027 · Arvada, CO · 5K

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Wild Horse Half
Sun 16 May 2027 · De Beque, CO · Half Marathon

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Colfax Marathon
Sun 16 May 2027 · Denver, CO · Marathon · Relay · Half Marathon · Urban 10 Miler · 5K
Relay leg of Denver's Colfax Marathon on Colfax Ave

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Angel Run at Red Leg Brewing
May 2027 · Colorado Springs, CO · 10K · 5K
Starts and finishes at a Colorado Springs brewery

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MTHCF 5K
May 2027 · Fruita, CO · 5K
Kicks off Fruita's Mike the Headless Chicken Festival

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North Fork 50 Mile/50K
May 2027 · Pine, CO · 50 Mile · 50K
A soft-surface ultra through Colorado pine forests and burn zones

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Spirit Trail Race
Sun 30 May 2027 · Buena Vista, CO · Marathon · Half Marathon · 9K
Trail race held during Buena Vista's Paddlefest

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Narrow Gauge 10 Mile
May 2027 · Durango, CO · 10 Mile
Named for Durango's historic narrow-gauge steam railroad

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BOLDERBoulder 10K
Mon 31 May 2027 · Boulder, CO · 10K
Colorados biggest 10K tradition on Memorial Day in Boulder

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← Colorado Oct Nov Dec Jan 2027 Feb 2027 Mar 2027 Apr 2027 Jun 2027 Jul 2027 Aug 2027 Sep 2027 Oct 2027

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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.