| 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 |
|---|---|---|---|
| 312-667 | Chicago | Cook | Landline |
| 312-831 | Chicago | Cook | Landline |
| 312-649 | Chicago | Cook | Landline |
| 312-508 | Chicago | Cook | Landline |
| 312-276 | Chicago | Cook | Landline |
| 312-905 | Chicago | Cook | Landline |
| 312-214 | Chicago | Cook | Landline |
| 312-793 | Chicago | Cook | Landline |
| 312-774 | Chicago | Cook | Wireless |
| 312-850 | Chicago | Cook | Landline |
| 312-368 | Chicago | Cook | Landline |
| 312-442 | Chicago | Cook | Landline |
| 312-561 | Chicago | Cook | Wireless |
| 312-351 | Chicago | Cook | Wireless |
| 312-266 | Chicago | Cook | Landline |
| 312-380 | Chicago | Cook | Landline |
| 312-245 | Chicago | Cook | Landline |
| 312-477 | Chicago | Cook | Wireless |
| 312-291 | Chicago | Cook | Landline |
| 312-670 | Chicago | Cook | Landline |