Boulder County claimed a population of 330,758 in the 2020 census. Both the county seat and most populous town are Boulder.
Named for Boulder City and Boulder Creek (due to the plentiful boulders found therein, of course), Boulder County was one of the original 17 counties created by the Territory of Colorado on November 1, 1861.
National protected areas include Arapaho National Forest, Roosevelt National Forest, Indian Peaks Wilderness, and James Peak Wilderness. Rocky Mountain National Park is found in Boulder County, northwest of the city of Boulder.
Visit the Boulder County Government website.
County Towns
- Allenspark
- Boulder
- Eldorado Springs
- Erie (part, extends to Weld Co)
- Jamestown
- Lafayette
- Longmont (party, extends to Weld Co)
- Louisville
- Lyons
- Nederland
- Niwot
- Pinecliffe
- Superior (part, extends to Jefferson Co)
- Ward
- Wondervu
Adjacent Counties
Special Events
- Jan – Lafayette Oatmeal Festival
- Mar – Frozen Dead Guy Days in Nederland
- Jun – High Peaks Art Festival in Nederland
- Jun-Aug – Colorado Shakespeare Festival in Boulder
- Jul – RockyGrass Festival in Lyons
- Jul – JUL-IPA in Boulder
- Aug – Boulder International Fringe Festival
- Aug – Rocky Mountain Folks Festival in Lyons
- Aug – Nedfest in Nederland
- Aug – Lafayette Peach Festival
- Sep – Lafayette Brew Fest
- Oct – Handmade In Colorado Expo in Boulder
