Founded in 1837, Stephenson County is one of 102 counties in the state of Illinois. Historically, Stephenson County was formed from Jo Daviess and Winnebago County. The city of Freeport is the county seat. With FIPS code of 177, Stephenson County has a population of 44,021 and area of 564 square miles (1,461 km2).
List of all cities in Stephenson County, IL alphabetically
| City/Town | Postal Code | Area Code |
| Cedarville, IL | 61013 | 815/779 |
| Dakota, IL | 61018 | 815/779 |
| Davis, IL | 61019 | 815/779 |
| Eleroy, IL | 61027 | 815/779 |
| Freeport, IL | 61032 | 815/779 |
| German Valley, IL | 61039 | 815/779 |
| Kent, IL | 61044 | 815/779 |
| Lena, IL | 61048 | 815/779 |
| Loran, IL | 61062 | 815/779 |
| McConnell, IL | 61050 | 815/779 |
| Oneco, IL | 61060 | 815/779 |
| Orangeville, IL | 61060 | 815/779 |
| Pearl City, IL | 61062 | 815/779 |
| Ridott, IL | 61067 | 815/779 |
| Rock City, IL | 61070 | 815/779 |
| Rock Grove, IL | 61070 | 815/779 |
| Scioto Mills, IL | 61032 | 815/779 |
| Waddams Grove, IL | 61048 | 815/779 |
| Winslow, IL | 61089 | 815/779 |