| 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 |
|---|---|---|---|
| 815-529 | Wonder Lake | Mchenry | Wireless |
| 815-545 | Joliet | Will | Wireless |
| 815-627 | Paw Paw | Lee | Landline |
| 815-736 | Newark | Kendall | Landline |
| 815-746 | Marseilles | La Salle | Landline |
| 815-506 | Union | Mchenry | Landline |
| 815-681 | Rockford | Winnebago | Landline |
| 815-526 | Crystal Lake | Mchenry | Landline |
| 815-981 | Ottawa | La Salle | Landline |
| 815-997 | Rockford | Winnebago | Landline |
| 815-463 | New Lenox | Will | Landline |
| 815-430 | Mchenry | Mchenry | Landline |
| 815-623 | Roscoe | Winnebago | Landline |
| 815-813 | Apple River | Jo Daviess | Landline |
| 815-302 | Joliet | Will | Wireless |
| 815-620 | Annawan | Henry | Landline |
| 815-373 | Elwood | Will | Landline |
| 815-461 | Romeoville | Will | Landline |
| 815-503 | Mendota | La Salle | Wireless |
| 815-714 | Joliet | Will | Landline |