Douglas County Flag

Douglas County

State:
Colorado
County Seat:
Castle Rock

Douglas County's 2026 population is estimated at 411,703, reflecting a 2.2% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Douglas County is the 6th largest county in Colorado. The 2010 population was 287,011 and has grown 43.45% since 2010.

411,703
Total Population
490
Population Density (mi²)
6
Population Rank (State)
8.9K 2.2%
Annual Population Growth

Douglas County Population

Demographics

Economics and Income Statistics