| 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 |
|---|---|---|---|
| 312-936 | Chicago | Cook | Wireless |
| 312-772 | Chicago | Cook | Wireless |
| 312-813 | Chicago | Cook | Wireless |
| 312-808 | Chicago | Cook | Landline |
| 312-281 | Chicago | Cook | Landline |
| 312-765 | Chicago | Cook | Landline |
| 312-688 | Chicago | Cook | Wireless |
| 312-215 | Prospect Heights | Cook | Wireless |
| 312-572 | Chicago | Cook | Landline |
| 312-617 | Chicago | Cook | Wireless |
| 312-279 | Chicago | Cook | Landline |
| 312-536 | Chicago | Cook | Wireless |
| 312-729 | Chicago | Cook | Landline |
| 312-660 | Chicago | Cook | Landline |
| 312-577 | Chicago | Cook | Landline |
| 312-661 | Chicago | Cook | Landline |
| 312-349 | Chicago | Cook | Wireless |
| 312-427 | Chicago | Cook | Landline |
| 312-889 | Chicago | Cook | Landline |
| 312-410 | Chicago | Cook | Landline |