Boulder
- County:
- Boulder County
- County Seat:
- Yes
- Area (mi²):
- 26.894
- State:
- Colorado
Boulder is a city located in Boulder County, Colorado. Boulder has a 2026 population of 106,803. It is also the county seat of Boulder County. Boulder is currently growing at a rate of 0.16% annually but its population has decreased by -1.49% since the most recent census, which recorded a population of 108,418 in 2020.