| Illinois | 
| State of Illinois - Phone Code and Area Codes for Mobile, Whatsapp and Text Messages | 
| Phone and Whatsapp Codes in Illinois / IL - Area Code : 312 Chicago | 
| Area Code : 773 Chicago | 
| Area Code : 630 Chicago suburbs | 
| Area Code : 847 Chicago suburbs | 
| Area Code : 708 NorthEast | 
| Area Code : 815 Northern | 
| Area Code : 224 | 
| Area Code : 331 | 
| Area Code : 464 overlay deferred - 872 overlay deferred | 
| Area Code : 217 South | 
| Area Code : 618 Southern | 
| Area Code : 779 | 
| Area Code : 779 | 
| Area Code : 309 West Central - | 
| US Code List of Codes in USA. Area Code and Phone Information by City and State. |