| Area Code | 312 |
| State | Illinois |
| Current Time in Area Code 312 | 312> CST |
| Timezone | Central Standard Time |
| Population (2020) | 5275541 |
| Adjacent Area Codes | 773,872 |
| 60601 |
| 60602 |
| 60603 |
| 60604 |
| 60605 |
| 60606 |
| 60607 |
| 60610 |
| 60611 |
| 60612 |
| 60616 |
| 60654 |
| 60661 |
| 60664 |
| 60669 |
| 60670 |
| 60673 |
| 60674 |
| 60675 |
| 60677 |
| 60680 |
| 60681 |
| 60684 |
| 60685 |
| 60686 |
| 60689 |
| 60690 |
| 60691 |
| 60693 |
| 60694 |
| 60695 |
| 60696 |
| 60697 |
| 60699 |
| Cook County |