Douglas County is a county located in the U.S. state of Colorado. As of the 2020 Census, the population was 357,978. The county is named in honor of U.S. Senator Stephen A. Douglas. The county seat is Castle Rock.
AdStay Updated on the COVID-19 Vaccine: Check Availability and Get Your Second Dose Now. Find a COVID Vaccine Location Near You and Make an Appointment for Your Second Dose.