• Top 10 in America USA Today 2024, 2025, 2026
  • #2 Fastest Growing Race in US - RunSignUp
  • Best Fall Marathons - Runners Wolrd
  • Top 10 in America USA Today
  • #2 Fastest Growing Race in US - RunSignUp
  • Best Fall Marathons - Runners Wolrd
  • Top 10 in America USA Today
  • #2 Fastest Growing Race in US - RunSignUp
  • Best Fall Marathons - Runners Wolrd
  • Top 10 in America USA Today
  • #2 Fastest Growing Race in US - RunSignUp
  • Best Fall Marathons - Runners Wolrd
Register

FULL MARATHON

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THE MARATHON
WORTH RUNNING

Boulderthon Full Marathon

Date: Sunday, September 27th 2026

Start Time: 7:00AM

Full Marathon Pacing Groups

3:00, 3:15, 3:30, 3:45, 4:00, 4:30, 5:00, 5:30

Pacing provided by BEAST Pacing

New Courses Announced! For our 6th Edition, we’re going back to our roots – now with even more beauty and speed.

Enjoy breathtaking views near the Reservoir, an epic Start & Finish in Downtown Boulder, and a 40–50% reduction in elevation gain.

This will be our most scenic and runnable course yet!

BOULDERTHON FULL MARATHON REGISTRATION

Registration for the Boulderthon Full Marathon is now open.

REGISTER