| 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 |
|---|---|---|---|
| 815-655 | Chadwick | Carroll | Landline |
| 815-750 | Marseilles | La Salle | Landline |
| 815-317 | Crescent City | Iroquois | Landline |
| 815-783 | Gilman | Iroquois | Landline |
| 815-474 | Joliet | Will | Wireless |
| 815-635 | Chatsworth | Livingston | Landline |
| 815-453 | Ashton | Lee | Landline |
| 815-650 | Freeport | Stephenson | Landline |
| 815-963 | Rockford | Winnebago | Landline |
| 815-486 | Donovan | Iroquois | Landline |
| 815-993 | Oglesby | La Salle | Wireless |
| 815-568 | Marengo | Mchenry | Landline |
| 815-871 | Rockford | Winnebago | Wireless |
| 815-467 | Minooka | Grundy | Landline |
| 815-841 | Mount Morris | Ogle | Landline |
| 815-369 | Lena | Stephenson | Landline |
| 815-633 | Loves Park | Winnebago | Landline |
| 815-207 | Joliet | Will | Landline |
| 815-518 | Coal City | Grundy | Landline |
| 815-962 | Rockford | Winnebago | Landline |