Douglas County Flag

Douglas County

State:
Colorado
County Seat:
Castle Rock

Douglas County's estimated 2026 population is 405,741 with a growth rate of 1.59% in the past year according to the most recent United States census data. Douglas County is the 6th largest county in Colorado. The 2010 population was 287,011 and has seen a growth of 41.37% since that time.

405,741
Total Population
482
Population Density (mi²)
6
Population Rank (State)
6.3K 1.59%
Annual Population Growth

Douglas County Population

Demographics

Economics and Income Statistics