| 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 |
|---|---|---|---|
| 815-560 | Harvard | Mchenry | Landline |
| 815-465 | Grant Park | Kankakee | Landline |
| 815-547 | Belvidere | Boone | Landline |
| 815-710 | Morris | Grundy | Landline |
| 815-390 | Braidwood | Will | Landline |
| 815-658 | Lanark | Carroll | Landline |
| 815-421 | Herscher | Kankakee | Landline |
| 815-347 | Wonder Lake | Mchenry | Wireless |
| 815-677 | Elizabeth | Jo Daviess | Landline |
| 815-899 | Sycamore | Dekalb | Landline |
| 815-477 | Crystal Lake | Mchenry | Landline |
| 815-368 | Lostant | La Salle | Landline |
| 815-831 | Davis | Stephenson | Landline |
| 815-894 | Ladd | Bureau | Landline |
| 815-780 | La Salle | La Salle | Landline |
| 815-497 | Compton | Lee | Landline |
| 815-459 | Crystal Lake | Mchenry | Landline |
| 815-381 | Rockford | Winnebago | Landline |
| 815-250 | La Salle | La Salle | Landline |
| 815-418 | Manhattan | Will | Landline |