| General Information about Area Code 312 | |
|---|---|
| Country | United States |
| State / Province / Territory | Illinois |
| Major City | Chicago |
| Time Zone | Central (UTC-06:00) |
| Prefix | Primary City | County | Phone Type |
|---|---|---|---|
| 312-943 | Chicago | Cook | Landline |
| 312-517 | Chicago | Cook | Landline |
| 312-924 | Chicago | Cook | Landline |
| 312-690 | Chicago | Cook | Landline |
| 312-382 | Chicago | Cook | Landline |
| 312-506 | Chicago | Cook | Landline |
| 312-253 | Chicago | Cook | Landline |
| 312-676 | Chicago | Cook | Landline |
| 312-273 | Chicago | Cook | Wireless |
| 312-885 | - | - | - |
| 312-333 | Chicago | Cook | Wireless |
| 312-322 | Chicago | Cook | Landline |
| 312-433 | Chicago | Cook | Landline |
| 312-563 | Chicago | Cook | Landline |
| 312-751 | Chicago | Cook | Landline |
| 312-836 | Chicago | Cook | Landline |
| 312-454 | Chicago | Cook | Landline |
| 312-816 | Western Springs | Cook | Wireless |
| 312-791 | Chicago | Cook | Landline |
| 312-869 | Chicago | Cook | Landline |