Boulder Rez Marathon
Boulder Rez Marathon circles reservoir-side dirt and trail with broad Flatirons views, offering a largely flat Colorado full with about 200 feet of gain.
Quick facts
- Reservoir-side dirt and trail
- Approximately 200 feet of gain
- Flatirons views
- Open, exposed Colorado course
About the Boulder Rez Marathon
Boulder Reservoir hosts this open-air marathon as the longest race in a multi-distance Saturday program. The Rez branding reflects the venue and distinguishes the event from Boulder's road races.
Course
The marathon uses mostly flat dirt and trail around Boulder Reservoir, with roughly 200 feet of total climbing. Repeated open stretches favor steady pacing but leave runners exposed to sun and wind.
Race-day weather
August mornings in Boulder may begin mild and become hot quickly under high-altitude sun. Reservoir wind and afternoon storms are possible, so early hydration and sun protection matter.
Past Boulder Rez Marathon dates and results
| Year | Date | Status | Results |
|---|---|---|---|
| 2026 | Saturday, August 15, 2026 | Results available | Open results |
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Boulder Rez Marathon FAQ
When is the Boulder Rez Marathon?
We're waiting for the finalized date for the 2027 Boulder Rez Marathon. The most recent running was on Saturday, August 15, 2026.
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