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Boulderthon: Boulder Marathon (Full, Half, 10k, 5k, Kids Run)

Sun October 8


After nearly tripling in size and selling out last year, Boulderthon has instituted a new 5,000 runner cap and is expected to sell out again. Register today!

Colorado’s Largest Fall Race Series: Run a 5k, 10k, Half, or Full, at the foothills of the Rockies, in the stunning running mecca of Boulder. Run the streets Olympians train on, then celebrate at our epic After Party in Downtown Boulder!

Boulderthon is one of the top-rated marathons in the United States: named #5 Best Half Marathon in the US by Active, as well as #1 Best in Colorado and #13 Most Beautiful Marathon in the World by HalfMarathons.Net, Boulderthon drew over 4,000 runners from all 50 states and 15 countries in 2022, nearly tripling in registration, and selling out.

Register with code RACECENTERAUGUST20 for $20 off the Half or Full Marathon and RACECENTERAUGUST10 for $10 off the 10K & 5K. Exp. 8/31

5K, 10K, Half Marathon, Marathon


Boulder, Colorado
Boulder, CO 80301 United States + Google Map