| 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 |
|---|---|---|---|
| 312-220 | Chicago | Cook | Landline |
| 312-381 | Chicago | Cook | Landline |
| 312-290 | Chicago | Cook | Wireless |
| 312-623 | Chicago | Cook | Wireless |
| 312-306 | Chicago | Cook | Landline |
| 312-726 | Chicago | Cook | Landline |
| 312-476 | Chicago | Cook | Landline |
| 312-316 | Chicago | Cook | Wireless |
| 312-802 | Chicago | Cook | Wireless |
| 312-332 | Chicago | Cook | Landline |
| 312-350 | Chicago | Cook | Wireless |
| 312-713 | Chicago | Cook | Wireless |
| 312-724 | Chicago | Cook | Landline |
| 312-556 | Chicago | Cook | Wireless |
| 312-325 | Chicago | Cook | Landline |
| 312-983 | Chicago | Cook | Landline |
| 312-596 | Chicago | Cook | Landline |
| 312-219 | Chicago | Cook | Wireless |
| 312-341 | Chicago | Cook | Landline |
| 312-314 | Western Springs | Cook | Wireless |