| 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 |
|---|---|---|---|
| 815-514 | Joliet | Will | Wireless |
| 815-385 | Mchenry | Mchenry | Landline |
| 815-995 | Dekalb | Dekalb | Landline |
| 815-481 | Brookfield | Cook | Wireless |
| 815-722 | Joliet | Will | Landline |
| 815-957 | Rockton | Winnebago | Landline |
| 815-280 | Joliet | Will | Landline |
| 815-353 | Wonder Lake | Mchenry | Wireless |
| 815-688 | Strawn | Livingston | Landline |
| 815-766 | Dekalb | Dekalb | Wireless |
| 815-775 | Woodstock | Mchenry | Wireless |
| 815-239 | Pecatonica | Winnebago | Landline |
| 815-516 | Rockford | Winnebago | Landline |
| 815-923 | Union | Mchenry | Landline |
| 815-209 | Rockford | Winnebago | Landline |
| 815-498 | Somonauk | Dekalb | Landline |
| 815-262 | Rockford | Winnebago | Wireless |
| 815-944 | Momence | Kankakee | Landline |
| 815-231 | Rockford | Winnebago | Landline |
| 815-890 | Rockford | Winnebago | Landline |