Race Start End City State
Manitou 5K Oct. 10, '26 Oct. 10, '26 Manitou Springs CO REGISTER
Halloween Trick or Trot Run 5K/10K/13.1 DENVER/AURORA Oct. 31, '26 Oct. 31, '26 Centennial CO REGISTER
Coffee Lovers Run 5K/10K/13.1 DENVER/AURORA Oct. 10, '26 Oct. 10, '26 Centennial CO REGISTER
Westy Half & 5k Oct. 11, '26 Oct. 11, '26 Westminster CO REGISTER
I Ain't Scared (of 5k) Oct. 31, '26 Oct. 31, '26 Thornton CO REGISTER
RMRR October Trophy Series Oct. 4, '26 Oct. 4, '26 Aurora CO REGISTER
Ghosts and Goblins 5K/10K Oct. 25, '26 Oct. 25, '26 Denver CO REGISTER
Bagel Run 5K/10K/13.1 DENVER/AURORA Oct. 10, '26 Oct. 10, '26 Centennial CO REGISTER
Rim to Rim Royal Gorge Races: 5K Road Run, Trail 8 Mile, Trail Half Marathon Oct. 3, '26 Oct. 3, '26 Canon City CO REGISTER
Windsor Marathon, Half Marathon, 10k, 5k & 1 Mile Run Oct. 4, '26 Oct. 4, '26 Windsor CO REGISTER
The Long View Marathon Oct. 10, '26 Oct. 10, '26 Fort Collins CO REGISTER
Spooky Sprint - Colorado Springs Oct. 31, '26 Oct. 31, '26 Colorado Springs CO REGISTER
I Can 5k Oct. 3, '26 Oct. 3, '26 Thornton CO REGISTER
YMCA of Pueblo Spooky Sprint 5K Oct. 24, '26 Oct. 24, '26 Pueblo CO REGISTER
Foundry Halloween 5k Oct. 31, '26 Oct. 31, '26 Steamboat Springs CO REGISTER
The Great Trailhead Foot Race 5 & 10 Miler Oct. 17, '26 Oct. 17, '26 Lakewood CO REGISTER
Rubey Rescue Run Oct. 4, '26 Oct. 4, '26 Aspen CO REGISTER
Lafayette Music Fest -5K - 10K Oct. 3, '26 Oct. 3, '26 Lafayette CO REGISTER
Durango Marathon Oct. 11, '26 Oct. 11, '26 Durango CO REGISTER
Spooky Sprint - Denver Oct. 3, '26 Oct. 3, '26 Denver CO REGISTER
Indian Creek Trail Runs Oct. 17, '26 Oct. 17, '26 Sedalia CO REGISTER
Colorado Springs Marathon, Half, 5K, and Kids K Oct. 3, '26 Oct. 3, '26 Colorado Springs CO REGISTER
HRCA Wildcat Mountain Trail Races Oct. 3, '26 Oct. 3, '26 Littleton CO REGISTER
Panda Waddle 5k Oct. 31, '26 Oct. 31, '26 Grand Junction CO  
Emerald Mountain Trail Run Oct. 3, '26 Oct. 3, '26 Steamboat Springs CO REGISTER
Blue Sky Trail Marathon & Half Marathon Oct. 17, '26 Oct. 18, '26 Fort Collins CO REGISTER
Apex Foundation Trick or Trot 5K & Halloween Hunt Oct. 24, '26 Oct. 24, '26 Arvada CO REGISTER
Witch Paddle Oct. 17, '26 Oct. 17, '26 Littleton CO REGISTER
Race to Cure Sarcoma Denver Oct. 24, '26 Oct. 24, '26 Denver CO REGISTER
Splashland Triathlon Oct. 3, '26 Oct. 3, '26 Alamosa CO REGISTER