Founded on 1861-11-01, Douglas County is one of 64 counties in the state of Colorado. Historically, Douglas County was formed from Created as one of the 17 original counties of the Territory of Colorado. The city of Castle Rock is the county seat. With FIPS code of 35, Douglas County has a population of 368,990 and area of 842.30 square miles (2,182 km2).
List of all cities in Douglas County, CO alphabetically
| City/Town | Postal Code | Area Code |
| Castle Rock, CO | 80104 | 303/720 |
| 80108 | 303/720 | |
| 80109 | 303/720 | |
| Deckers, CO | 80135 | 303/720 |
| Franktown, CO | 80116 | 303/720 |
| Highlands Ranch, CO | 80126 | 303/720 |
| 80129 | 303/720 | |
| 80130 | 303/720 | |
| 80163 | 303/720 | |
| Larkspur, CO | 80118 | 303/720 |
| Littleton, CO | 80124 | 303/720 |
| 80125 | 303/720 | |
| 80126 | 303/720 | |
| 80129 | 303/720 | |
| 80130 | 303/720 | |
| 80163 | 303/720 | |
| Lone Tree, CO | 80124 | 303/720 |
| Louviers, CO | 80131 | 303/720 |
| Parker, CO | 80134 | 303/720 |
| 80138 | 303/720 | |
| Sedalia, CO | 80135 | 303/720 |
Map of Cities in Douglas County, CO
