| General Information about Area Code 815 | |
|---|---|
| Country | United States |
| State / Province / Territory | Illinois |
| Major City | Rockford |
| Time Zone | Central (UTC-06:00) |
| Prefix | Primary City | County | Phone Type |
|---|---|---|---|
| 815-456 | Ashton | Lee | Landline |
| 815-713 | Rockford | Winnebago | Landline |
| 815-489 | Rockford | Winnebago | Landline |
| 815-942 | Morris | Grundy | Landline |
| 815-202 | Oglesby | La Salle | Wireless |
| 815-851 | Bradley | Kankakee | Wireless |
| 815-307 | Mchenry | Mchenry | Landline |
| 815-906 | Mount Carroll | Carroll | Landline |
| 815-225 | Milledgeville | Carroll | Landline |
| 815-240 | Rockford | Winnebago | Landline |
| 815-559 | Fulton | Whiteside | Landline |
| 815-778 | Lyndon | Whiteside | Landline |
| 815-875 | Princeton | Bureau | Landline |
| 815-734 | Mount Morris | Ogle | Landline |
| 815-382 | Wonder Lake | Mchenry | Wireless |
| 815-878 | Princeton | Bureau | Wireless |
| 815-951 | Amboy | Lee | Landline |
| 815-297 | Freeport | Stephenson | Landline |
| 815-346 | Gardner | Grundy | Landline |
| 815-793 | Sycamore | Dekalb | Wireless |