Castle Rock
- County:
- Douglas County
- County Seat:
- Yes
- Area (mi²):
- 34.742
- State:
- Colorado
Castle Rock is a town located in Douglas County, Colorado. Castle Rock has a 2026 population of 83,213. It is also the county seat of Douglas County. Castle Rock is currently growing at a rate of 1.91% annually and its population has increased by 12.62% since the most recent census, which recorded a population of 73,888 in 2020.