Bolder Boulder. The Bolder Boulder (styled as BOLDERBoulder and previously BolderBOULDER) is an annual 10-kilometer run in Boulder, Colorado. The most recent race featured over 54,000 runners, walkers, and wheelchair racers, making it the second largest 10k race in the US and the fifth largest road race in the world.
Organizers have dedicated three starting waves to current and former members of the U.S. armed forces . On March 16, 2020, organizers of the Bolder Boulder race initially decided to postpone the race, usually held on Memorial Day, until Labor Day due to COVID-19. On June 1, organizers then decided to cancel the 2020 race entirely.