The Bolder Boulder is an annual 10-kilometer run in Boulder, Colorado. The 2007 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. It has one of the largest non-marathon prize purses in road racing.

Boulder is a home rule city and the county seat of Boulder County, Colorado, United States. It is the largest city in Boulder County, with a population of 108,250 at the 2020 United States census, making it the 12th-most populous city in Colorado. Boulder is the principal city of the Boulder, CO Metropolitan Statistical Area and part of the Front Range Urban Corridor.