Difficulty
Marathon Index Score
Nästa lopp
16 maj 2026
The Bolder Boulder courses from the University of Colorado campus down Flagstaff Road with scenic mountain views of the Flatirons, then through downtown Boulder with its iconic Pearl Street Mall finish. The race features a net downhill elevation profile with rolling terrain through residential neighborhoods and parks.
Late May in Boulder offers pleasant spring weather with cool mornings and mild afternoons. Altitude of 5,430 feet can affect sea-level runners during acclimatization.
The Race
Boulder
The Bolder Boulder was founded in 1979, during the golden age of mass-participation running. Now 47 years old, it has established itself as a beloved fixture in Boulder, growing from its early editions into a race with genuine character and loyal following.
Moses Kemboi set the blistering course record of 00:59:43 in 2016, proving this course can produce world-class half marathon times. The flat roads of Boulder have become a proving ground for the fastest runners on the planet.
The Bolder Boulder route is one of those courses where runners forget their pace and reach for their phones. The scenery through Boulder and its surroundings has earned this race a reputation as one of the most photogenic in North America.
With 38,000 finishers and spectators lining the course deep, the Bolder Boulder generates an atmosphere that carries runners through the hard miles. The crowd support in Boulder is not polite applause — it's visceral, personal, and often the difference between hitting the wall and breaking through it.
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00:59:43
Moses Kemboi (2016)
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