Course
The marathon runs from 21st and Pearl through Boulder's back roads and foothills to a downtown finish at 14th and Spruce. Hydration stations are spaced every 3-4 miles, with energy gels available at three on-course stops.
Key dates
- ★Race daySeptember 2027 · date to be announced
About
Boulderthon is an annual running festival in downtown Boulder, Colorado, featuring a full marathon, half marathon, 10K, and 5K races. The event showcases the scenic beauty of Boulder with a fast, point-to-point course starting and finishing in the heart of the city.
Save Boulderthon: Downtown Boulder Marathon to your season and RunCalendar reminds you the morning entries open and before they close. Free on iPhone, no account needed.
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Estes Epic
Rugged singletrack ultra through Rocky Mountain National Park
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Sawatch Ascent
High alpine 50k climbing 7000 feet beneath the Sawatch peaks
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Rim to Rim Royal Gorge Races
Cross Americas highest suspension bridge over the gorge
A confirmed date shows its day; a provisional one shows only its month, because we won't claim a day we don't have. This page is rebuilt every night from the RunCalendar catalogue.