| 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 |
|---|---|---|---|
| 312-359 | Chicago | Cook | Wireless |
| 312-418 | Chicago | Cook | Wireless |
| 312-395 | Chicago | Cook | Landline |
| 312-702 | Chicago | Cook | Landline |
| 312-863 | Chicago | Cook | Landline |
| 312-387 | Chicago | Cook | Wireless |
| 312-331 | Prospect Heights | Cook | Wireless |
| 312-436 | Chicago | Cook | Landline |
| 312-894 | Chicago | Cook | Landline |
| 312-921 | Chicago | Cook | Landline |
| 312-226 | Chicago | Cook | Landline |
| 312-501 | Brookfield | Cook | Wireless |
| 312-853 | Chicago | Cook | Landline |
| 312-353 | Chicago | Cook | Landline |
| 312-385 | Chicago | Cook | Landline |
| 312-672 | Chicago | Cook | Landline |
| 312-217 | Chicago | Cook | Wireless |
| 312-929 | Chicago | Cook | Landline |
| 312-429 | Chicago | Cook | Landline |
| 312-848 | Chicago | Cook | Wireless |