COUNTY · CO
Boulder County, Colorado
Boulder County is a county in Colorado with FIPS code 08013 and an estimated population of 326,831 (Census 2023), 9th largest of 64 in the state.
County facts
- Name
- Boulder County
- State
- Colorado
- Type
- county
- FIPS code
- 08013
- State FIPS
- 08
- Population (2023)
- 326,831
- Change since 2020
- -1.2%
- State rank
- 9 of 64
Population is the Census Bureau’s Vintage 2023 estimate.
Major cities in Boulder County
Other counties in Colorado
Questions
What is the FIPS code for Boulder County?
Boulder County, Colorado has the five-digit FIPS code 08013: 08 for the state and 013 for the county.
What state is Boulder County in?
Boulder County is in Colorado.
How do I know if an address is in this county?
Use the address lookup. ZIP codes and city names can cross county lines, so an address is the reliable check.
Sources: U.S. Census Bureau geographic reference files; Census Bureau Population Estimates, Vintage 2023. Last reviewed 2026-10-27.