Congratulations to the 4,000+ Boulderthon 2022 Finishers! View Results & Photos here.
Finish line of Boulderthon at the end of the street

Boulderthon is One of the Top-Rated Colorado Marathons

Join us on Sunday, Oct 8, 2023 for the 3rd annual Boulderthon Marathon in Boulder, Colorado. The course starts at Boulder Reservoir, and takes you through the beautiful back roads of Boulder, Colorado at the foothills of the Flatirons, before winding you to Downtown Boulder for an incredible finish on the historic Pearl Street Mall! The Boulderthon is a certified Boston Qualifier and is the perfect Fall race to test your end of the season fitness!

Boulderthon is also a Boston Marathon Qualifier!


Full Marathon Information

Date: October 8, 2023

Start Time: 8am

Course Close: 2pm

Elevation Gain: 1582 feet

Course Map:

Course Map

Boulderthon Marathon Registration

Registration for the Boulderthon Marathon is open. You can register online or show up early and register on the day of the race.

Boulderthon also offers a Kids Run and 5k on Saturday, October 7th. On Sunday, October 8th our other races include a 10k and Half Marathon.


Race Packet Pick Up:

  • Boulderthon offers Early Packet Pickup (open to all) beginning Saturday, 9/30/23 through Thursday, 10/5/23 at Boulder Running Company, 2775 Pearl St, Boulder, CO 80302, during their normal hours.

  • Our Official Expo & Packet Pickup will take place on Pearl St Mall between 14th & 15th, on Friday, 10/6/23, from 2pm-6pm, and Saturday, 10/7/23 from 10am-4pm.

Getting There:

  • All Half Marathon runners will choose a transportation option (either Shuttle or Runner Drop Off Pass).

  • Shuttle Transportation is for the Half & Full Marathon only. Shuttles depart from Boulder High School beginning at 5am and transport Half & Full Marathon runners to the Start Line at the Boulder Reservoir. Shuttle rides are approximately 20 minutes.

  • Due to space restraints at Boulder Reservoir, all runners being dropped off at the Reservoir will require a Runner Drop Off Pass. No drop offs are allowed without a Pass.

Where Do I Park?

Whether you are boarding our Shuttle at Boulder High School (limited parking is available at Boulder High School on Race Morning) or planning on cheering runners on Pearl between 15th and 17th, here are the BEST FREE GARAGES to park in on Boulderthon Race Weekend.Parking Map


Gear Check

  • Your Goodie Bag is your Official Race Check Bag
  • Gear Check is available at the start
    • Please bring your Official Gear Check Bag to the Start and safety pin your Gear Check Tear-Off at the bottom of your bib to the top of your Official Gear-Check Bag.
  • We will transport anything you put in your Official Gear Check Bag to the Finish Area for you.
  • Please plan for chilly weather! Colorado can be chilly in October, with lows of 40 degrees in the morning. Plan on extra layers and check them into your Official Gear Check Bag.

Course Support

  • There will be water stations near miles 2, 4, 7, 8, 10, 12, 13.5, 16, 17, 19, 21, 23, 24, and 25.5.
  • Skratch Labs Hydration Mix will be available near miles 7, 10, 12, 17, 19, 23, and 25.5.
  • The Skratch Labs Hydration Mix flavors will be Lemon Lime & Fruit Punch.
  • Port-a-Potties will be available on the course slightly before miles 2, 4, 7, 9, 10, 12, 12.5, 13.5, 15.5, 17, 19, 19.5, 21, 22, 22.5, 23, 23.5, 24, and 24.5.
  • A number of highly trained physicians, nurses, physical therapists and other medical personnel will be on hand throughout race weekend. There will be medical stations near miles 6, 9, 12.5, 17, 19.5, 22 and 23.5, with a comprehensive set-up in the runner services area at the finish line. There will be a number of mobile units moving throughout the course. These units will be staffed by paramedics, EMTs and marathon staff. There will also be ambulances stationed at the finish line and throughout the course.

After Party & Cheer Spots

  • Cheer runners on at the Finish! First 250 spectators will get cowbells. Join the fun at Pearl & 15th St, including our first-of-its-kind finish at the Pearl Street Mall!
  • You can also cheer runners on throughout the course at any of our Hydration Stations!
  • In addition, our Designated Cheer Stations will be:
    • Pearl Street Finish- between 15th & 17th
    • Valmont City Park (on Multi-Use Path)
  • Official After Party is at Avanti F+B, at Pearl & 15th.

Boulderthon Marathon Reviews

"This was by far one of the best races I’ve participated in - Aid stations were dispersed well and there was so much help and encouragement from the volunteers and police officers. Thank you thank you thank you." - Miranda
"Fun course, positive vibes, beautiful views and just enough support along the way. Thanks to all who helped make this race happen. I’ll be back every year. Perfect Race." - Jess
“I've run nearly 50 marathons and/or half marathons and this ranks among the very best. Race day execution was flawless and I echo the previous comments about the professional staff and well organized volunteers groups. Looking forward to next year already!” - Brad