| 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 |
|---|---|---|---|
| 312-443 | Chicago | Cook | Landline |
| 312-895 | Chicago | Cook | Landline |
| 312-842 | Chicago | Cook | Landline |
| 312-334 | Chicago | Cook | Landline |
| 312-416 | Chicago | Cook | Landline |
| 312-204 | Chicago | Cook | Landline |
| 312-248 | Chicago | Cook | Wireless |
| 312-265 | Chicago | Cook | Landline |
| 312-942 | Chicago | Cook | Landline |
| 312-601 | Chicago | Cook | Landline |
| 312-755 | Chicago | Cook | Landline |
| 312-939 | Chicago | Cook | Landline |
| 312-363 | Chicago | Cook | Landline |
| 312-372 | Chicago | Cook | Landline |
| 312-759 | Chicago | Cook | Landline |
| 312-669 | Chicago | Cook | Landline |
| 312-231 | Medinah | Dupage | Wireless |
| 312-345 | Chicago | Cook | Landline |
| 312-685 | Chicago | Cook | Wireless |
| 312-370 | Chicago | Cook | Wireless |