October 2026 races in Denver–Boulder

There are 27 running events listed in Denver–Boulder for October 2026 — 24 5K, 9 10K, 6 Half Marathon, 5 Trail Run — starting with Big Waves Family 5K run/walk on Sat, Oct 3, 2026. Every listing shows the date, venue, and distances, with a direct link to registration.

• Sat, Oct 3, 2026 Big Waves Family 5K run/walk 397 W 148th Ave · Westminster, CO · From $45 5K Road
• Sat, Oct 3, 2026 HRCA Wildcat Mountain Trail Races 11033 Monarch Blvd · Littleton, CO · From $10 10KTrail Run Trail
• Sat, Oct 3, 2026 Spooky Sprint - Denver Chatfield State Park · Littleton, CO · From $20 5K10KHalf Marathon Road
• Sat, Oct 3, 2026 I Can 5k Carpenter Park Fields · Thornton, CO 5K Road
• Sat, Oct 3, 2026 Lafayette Music Fest -5K - 10K 400 W South Boulder Rd Suite · Lafayette, CO · From $40 5K10K Road
• Sun, Oct 4, 2026 Evergreen Mountain Weeknight Race 5300 S Olive Rd, · Evergreen, CO · From $25 Trail Run Trail
• Sun, Oct 4, 2026 RMRR October 5k/8mi 16002 E Smith Rd. · Aurora, CO · From $10 5K Road
• Sat, Oct 10, 2026 Bagel Run 5K/10K/13.1 DENVER/AURORA Piney Creek Hollow Park (Course Map will be emailed) · Centennial, CO · From $30 5K10KHalf Marathon Road
• Sat, Oct 10, 2026 Coffee Lovers Run 5K/10K/13.1 DENVER/AURORA Piney Creek Hollow Park (Course Map will be emailed) · Centennial, CO · From $30 5K10KHalf Marathon Road
• Sat, Oct 10, 2026 Suffer Better 10th Annual Fall Trail Runs Staunton State Park · Pine, CO · From $25 5KTrail Run Trail
• Sat, Oct 10, 2026 Kipling Villas 5K - 2026 9706 W Walker Pl · Littleton, CO · From $15 5K Road
• Sun, Oct 11, 2026 Westy Half & 5k 10600 Westminster Blvd · From $30 5KHalf Marathon Road
• Sun, Oct 11, 2026 Your Story Isn't Over 5k/10k/Kids 1-Mile 6301 S University Blvd · Littleton, CO · From $20 5K10K Road
• Sat, Oct 17, 2026 Indian Creek Trail Runs 2499 Pine Creek Rd · Sedalia, CO · From $30 5KTrail Run Trail
• Sat, Oct 17, 2026 Living Water 5K and Family Fun Run 4601 W. 46th Ave · Denver, CO · From $30 5K Road
• Sat, Oct 17, 2026 The Great Trailhead Foot Race 5 & 10 Miler 15600 W Morrison Rd. · Lakewood, CO · From $55 Trail Run Trail
• Sun, Oct 18, 2026 The Palmer Lake .5K (Yes "Point" 5) 104 CO-105 · Palmer Lake, CO · From $15 5K Road
• Wed, Oct 21, 2026 DU Crimson Classic 5K Run/1.5 Mile Walk Carnegie Green, University of Denver 5K Road
• Sat, Oct 24, 2026 Race to Cure Sarcoma Denver Berkeley Lake Park · Denver, CO · From $10 5K Road
• Sat, Oct 24, 2026 Apex Foundation Trick or Trot 5K & Halloween Hunt Powered by REP Fitness 13150 W 72nd Avenue · Arvada, CO · From $10 5K Road
• Sat, Oct 24, 2026 YMCA Creepy Crawl 5K presented by Corwin Honda Santa Fe Trailhead · Palmer Lake, CO · From $40 5K Road
• Sun, Oct 25, 2026 Ghosts and Goblins 5K/10K City Park · Denver, CO · From $30 5K10K Road
• Sun, Oct 25, 2026 The 14th Annual Odyssey Odyssey - 2026 101 Yosemite Street (Great Lawn Park) · Denver, CO 5K Road
• Sat, Oct 31, 2026 Halloween Trick or Trot Run 5K/10K/13.1 DENVER/AURORA Piney Creek Hollow Park (Course Map will be emailed) · Centennial, CO · From $30 5K10KHalf Marathon Road
• Sat, Oct 31, 2026 PB&J Fuel Run 5K/10K/13.1 DENVER/AURORA Piney Creek Hollow Park (Course Map will be emailed) · Centennial, CO · From $30 5K10KHalf Marathon Road
• Sat, Oct 31, 2026 I Ain't Scared (of 5k) Colorado and 108th Ave · Thornton, CO · From $29 5K Road
• Sat, Oct 31, 2026 Halloween Fun Run 5k & 1mile - Zombie Theme 320 Chicago Creek Rd · Idaho Springs, CO · From $20 5K Road

Quick answers

How many races are there in Denver–Boulder in October 2026?

27 running events are listed in Denver–Boulder for October 2026, from Big Waves Family 5K run/walk on Sat, Oct 3, 2026 to Halloween Fun Run 5k & 1mile - Zombie Theme on Sat, Oct 31, 2026. Every listing links directly to registration.

What distances can I race in Denver–Boulder in October?

The October 2026 calendar in Denver–Boulder includes 24 5K, 9 10K, 6 Half Marathon, 5 Trail Run.

What is the first race of October 2026 in Denver–Boulder?

Big Waves Family 5K run/walk on Sat, Oct 3, 2026 at 397 W 148th Ave.