Found 211 races

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Connect with runners, find training partners, and celebrate every finish together

OCT
3

Littleton, CO
• 8.5 miles
$10 -$80
The Wildcat Mountain Trail Races showcase some of the most scenic terrain in the HRCA Backcountry Wilderness Area, giving runners a true taste of the rolling hills, open views, and natural beauty...
10K
13
OCT
3

Thornton, CO
• 19.7 miles
You CAN 5k.  This event is for EVERY ONE.  EVERY BODY.  You won't get lost.  You won't get forgotten.  You'll run (or jog or walk or crawl) a clearly marked 5k course with friendly volunteers...
5K
29
OCT
3

Lafayette, CO
• 29.4 miles
$45 -$75
Lafayette Music Fest is put on by Rock for the People, a 501(c)(3) nonprofit organization in Lafayette, CO with the mission of building an inclusive live music community by offering free and...
5K 10K
8
OCT
3

Littleton, CO
• 10.4 miles
$90 -$120
What Is OUTLAST? OUTLAST is a 6-hour trail endurance challenge where runners complete a 5K every hour, on the hour. Each lap must be finished within the hour to stay in the event. If you finish...
1
OCT
3

Broomfield, CO
• 28.4 miles
$15 -$55
Prospect Ridge Academy is thrilled to present our 16th Annual Miner Gold Rush and Fall Festival! All proceeds will benefit Prospect Ridge Academy, a public charter school providing a rigorous,...
1m 5K
6
OCT
3

Loveland, Colorado
• 34.0 miles
Experience the ultimate Colorado adventure at Boyd Lake State Park! This event pairs you and your dog for a scenic run filled with fun, beginner-friendly obstacles. It’s all about local vibes,...
2m
1
15
OCT
4

Lorton, VA
• 5.0 miles
$50 -$67
Located just south of the Capital Beltway in Lorton, this beautiful race course includes a mixture of forested and open meadow singletrack meandering through 1600 acres of the former prison...
5m 10m
OCT
4

Aurora, CO
• 10.9 miles
$10 -$15
Rocky Mountain Road Runners holds a monthly Trophy Series in the Denver area.  We provide a low-key, low-cost racing environment. Everyone is welcome to run with us! The 8mi race uses a handicap...
5K 8m
37
OCT
10

Fort Collins, CO
• 45.2 miles
$35 -$120
Join us on a journey from Fort Collins to Loveland. The marathon begins at Edora Park in Fort Collins and ends at Fairgrounds Park in Loveland. The half-marathon starts at Fossil Creek Park and...
5K Half Marathon Marathon
52
OCT
11

Fort Collins, CO
• 47.6 miles
This fun run is held on national coming out day this out and back Greenway 5K is here to celebrate everyone and anyone! There will be an unofficial clock and a mini award ceremony after. this is...
5K
OCT
11

Westminster, CO
• 22.9 miles
$45 -$85
Join the WESTY HALF and 5k this fall! The Hometown Race Series features half marathons and 5k distance events in outlying communities outside the Denver and Boulder metro areas.  Whatever...
5K Half Marathon
86
OCT
17

Fort Collins, CO
• 43.5 miles
$100 -$130
Welcome to the Blue Sky Trail Marathon & Half, Fort Collins's original and only trail marathon. Taking place on the trails between Horsetooth Mountain Park and the Devil's Backbone Open Space,...
Half Marathon Marathon
OCT
17

Sedalia, CO
• 12.7 miles
$50 -$170
The Human Potential Running Series PresentsThe Indian Creek Trail Runs @ Indian Creek Campground The Indian Creek Trail Runs is the oldest official race of HPRS and is also known as our annual...
55K
OCT
17

Denver, CO
• 15.9 miles
$30
Participants joining our inaugural annual 5K Run/Walk will help bring clean, sustainable water solutions to communities in need and support our disaster response initiatives. We will be hosting...
5K
OCT
17

Lakewood, CO
• 15.9 miles
$65 -$90
Welcome to the Great Trailhead Foot Race at Bear Creek Lake Park!  Featuring legitimate TRAILS in the shadow of Denver's skyline, you'll love the single-track and dirt as you race 5 miles, or a...
5m 10m
60
OCT
18

Denver, CO
• 11.7 miles
10K Half Marathon
32
OCT
24

Arvada, CO
• 21.8 miles
$10 -$55
Voted Best of the Best in Arvada for Non Profit Events by Colorado Community Media! Join the Apex Foundation for the 6th Anniversary Trick or Trot 5K, presented by Intermountain Health! Runners...
5K
17
OCT
25

Denver, CO
• 11.2 miles
$30 -$50
The Ghosts & Goblins 5K/10K is a family, friendly event to celebrate the upcoming holiday season. Start your holiday traditions with a fun morning of fitness and friends by joining us at Denver’s...
5K 10K
52
OCT
25

Denver, CO
• 8.5 miles
The Odyssey Odyssey Fun Run is entering its 14th year. It has always been centered around having fun and exercising our bodies.  It is an all-inclusive event, which is why all the races are FREE...
1m 5K
77
OCT
31

Idaho Springs, CO
• 32.4 miles
$20
🎃 Halloween Fun Run – 5K & 1 Mile (Zombie Theme)Saturday, October 25, 2025 • 10 AM – 12 PM320 Chicago Creek Rd, Idaho Springs, CO Whether you shuffle like the undead, sprint like you're being...
1m 5K
10