Boulder County Flag

Boulder County

State:
Colorado
County Seat:
Boulder

Boulder County's 2026 population is estimated at 327,635, reflecting a -0.28% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Boulder County is the 9th largest county in Colorado. The 2010 population was 295,056 and has grown 11.04% since 2010.

327,635
Total Population
451
Population Density (mi²)
9
Population Rank (State)
-925 -0.28%
Annual Population Growth

Boulder County Population

Demographics

Economics and Income Statistics