| 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 |
|---|---|---|---|
| 815-725 | Joliet | Will | Landline |
| 815-423 | Elwood | Will | Landline |
| 815-880 | Woodstock | Mchenry | Landline |
| 815-494 | Rockford | Winnebago | Wireless |
| 815-292 | Roscoe | Winnebago | Landline |
| 815-324 | Ottawa | La Salle | Landline |
| 815-936 | Kankakee | Kankakee | Landline |
| 815-573 | Kankakee | Kankakee | Landline |
| 815-938 | Forreston | Ogle | Landline |
| 815-349 | Mchenry | Mchenry | Landline |
| 815-973 | Dixon | Lee | Wireless |
| 815-392 | Kinsman | Grundy | Landline |
| 815-903 | Mchenry | Mchenry | Wireless |
| 815-748 | Dekalb | Dekalb | Landline |
| 815-343 | Oglesby | La Salle | Wireless |
| 815-339 | Granville | Putnam | Landline |
| 815-425 | Crystal Lake | Mchenry | Landline |
| 815-527 | Woodstock | Mchenry | Landline |
| 815-310 | Utica | La Salle | Landline |
| 815-251 | Sterling | Whiteside | Landline |