| City | Area Code | Dialing Code |
|---|---|---|
| Addison | 331 | +1 331 |
| Addison | 630 | +1 630 |
| Algonquin | 224 | +1 224 |
| Algonquin | 847 | +1 847 |
| Arlington Heights | 224 | +1 224 |
| Arlington Heights | 847 | +1 847 |
| Bartlett | 331 | +1 331 |
| Bartlett | 630 | +1 630 |
| Batavia | 331 | +1 331 |
| Batavia | 630 | +1 630 |
| Belleville | 618 | +1 618 |
| Bellwood | 708 | +1 708 |
| Belvidere | 779 | +1 779 |
| Belvidere | 815 | +1 815 |
| Bensenville | 331 | +1 331 |
| Bensenville | 630 | +1 630 |
| Berwyn | 708 | +1 708 |
| Bloomingdale | 331 | +1 331 |
| Bloomingdale | 630 | +1 630 |
| Bloomington | 309 | +1 309 |
| Blue Island | 708 | +1 708 |
| Bolingbrook | 331 | +1 331 |
| Bolingbrook | 630 | +1 630 |
| Buffalo Grove | 224 | +1 224 |
| Buffalo Grove | 847 | +1 847 |
| Burbank | 708 | +1 708 |
| Calumet City | 708 | +1 708 |
| Carbondale | 618 | +1 618 |
| Carol Stream | 331 | +1 331 |
| Carol Stream | 630 | +1 630 |
| Carpentersville | 224 | +1 224 |
| Carpentersville | 847 | +1 847 |
| Champaign | 217 | +1 217 |
| Charleston | 217 | +1 217 |
| Chicago Heights | 708 | +1 708 |
| Cicero | 708 | +1 708 |
| Collinsville | 618 | +1 618 |
| Crystal Lake | 779 | +1 779 |
| Crystal Lake | 815 | +1 815 |
| Danville | 217 | +1 217 |
| Darien | 331 | +1 331 |
| Darien | 630 | +1 630 |
| Decatur | 217 | +1 217 |
| DeKalb | 779 | +1 779 |
| DeKalb | 815 | +1 815 |
| Des Plaines | 224 | +1 224 |
| Des Plaines | 847 | +1 847 |
| Dolton | 708 | +1 708 |
| Downers Grove | 331 | +1 331 |
| Downers Grove | 630 | +1 630 |
| East Alton | 618 | +1 618 |
| East Moline | 309 | +1 309 |
| East Peoria | 309 | +1 309 |
| East Saint Louis | 618 | +1 618 |
| Edwardsville | 618 | +1 618 |
| Elk Grove Village | 224 | +1 224 |
| Elk Grove Village | 847 | +1 847 |
| Elmhurst | 331 | +1 331 |
| Elmhurst | 630 | +1 630 |
| Elmwood Park | 708 | +1 708 |
| Evanston | 224 | +1 224 |
| Evanston | 847 | +1 847 |
| Evergreen Park | 708 | +1 708 |
| Freeport | 779 | +1 779 |
| Freeport | 815 | +1 815 |
| Galesburg | 309 | +1 309 |
| Glen Ellyn | 331 | +1 331 |
| Glen Ellyn | 630 | +1 630 |
| Glendale Heights | 331 | +1 331 |
| Glendale Heights | 630 | +1 630 |
| Glenview | 224 | +1 224 |
| Glenview | 847 | +1 847 |
| Granite City | 618 | +1 618 |
| Gurnee | 224 | +1 224 |
| Gurnee | 847 | +1 847 |
| Hanover Park | 331 | +1 331 |
| Hanover Park | 630 | +1 630 |
| Harvey | 708 | +1 708 |
| Highland Park | 224 | +1 224 |
| Highland Park | 847 | +1 847 |
| Hoffman Estates | 224 | +1 224 |
| Hoffman Estates | 847 | +1 847 |
| Joliet | 779 | +1 779 |
| Joliet | 815 | +1 815 |
| Kankakee | 779 | +1 779 |
| Kankakee | 815 | +1 815 |
| Lake Forest | 224 | +1 224 |
| Lake Forest | 847 | +1 847 |
| Lake in the Hills | 224 | +1 224 |
| Lake in the Hills | 847 | +1 847 |
| Lansing | 708 | +1 708 |
| Libertyville | 224 | +1 224 |
| Libertyville | 847 | +1 847 |
| Lisle | 331 | +1 331 |
| Lisle | 630 | +1 630 |
| Lombard | 331 | +1 331 |
| Lombard | 630 | +1 630 |
| Loves Park | 779 | +1 779 |
| Loves Park | 815 | +1 815 |
| Machesney Park | 779 | +1 779 |
| Machesney Park | 815 | +1 815 |
| Maywood | 708 | +1 708 |
| McHenry | 779 | +1 779 |
| McHenry | 815 | +1 815 |
| Melrose Park | 708 | +1 708 |
| Moline | 309 | +1 309 |
| Morton Grove | 224 | +1 224 |
| Morton Grove | 847 | +1 847 |
| Mount Prospect | 224 | +1 224 |
| Mount Prospect | 847 | +1 847 |
| Mundelein | 224 | +1 224 |
| Mundelein | 847 | +1 847 |
| Naperville | 331 | +1 331 |
| Naperville | 630 | +1 630 |
| Niles | 224 | +1 224 |
| Niles | 847 | +1 847 |
| Normal | 309 | +1 309 |
| North Aurora | 331 | +1 331 |
| North Aurora | 630 | +1 630 |
| North Chicago | 224 | +1 224 |
| North Chicago | 847 | +1 847 |
| Northbrook | 224 | +1 224 |
| Northbrook | 847 | +1 847 |
| O'Fallon | 618 | +1 618 |
| Oak Forest | 708 | +1 708 |
| Oak Lawn | 708 | +1 708 |
| Oak Park | 708 | +1 708 |
| Orland Park | 708 | +1 708 |
| Palatine | 224 | +1 224 |
| Palatine | 847 | +1 847 |
| Park Forest | 708 | +1 708 |
| Park Ridge | 224 | +1 224 |
| Park Ridge | 847 | +1 847 |
| Pekin | 309 | +1 309 |
| Peoria | 309 | +1 309 |
| Quincy | 217 | +1 217 |
| Rock Island | 309 | +1 309 |
| Rockford | 779 | +1 779 |
| Rockford | 815 | +1 815 |
| Rolling Meadows | 224 | +1 224 |
| Rolling Meadows | 847 | +1 847 |
| Romeoville | 779 | +1 779 |
| Romeoville | 815 | +1 815 |
| Roselle | 331 | +1 331 |
| Roselle | 630 | +1 630 |
| Round Lake Beach | 224 | +1 224 |
| Round Lake Beach | 847 | +1 847 |
| Saint Charles | 331 | +1 331 |
| Saint Charles | 630 | +1 630 |
| Schaumburg | 224 | +1 224 |
| Schaumburg | 847 | +1 847 |
| Skokie | 224 | +1 224 |
| Skokie | 847 | +1 847 |
| South Elgin | 224 | +1 224 |
| South Elgin | 847 | +1 847 |
| South Holland | 708 | +1 708 |
| Springfield | 217 | +1 217 |
| Streamwood | 331 | +1 331 |
| Streamwood | 630 | +1 630 |
| Tinley Park | 708 | +1 708 |
| Urbana | 217 | +1 217 |
| Vernon Hills | 224 | +1 224 |
| Vernon Hills | 847 | +1 847 |
| Villa Park | 331 | +1 331 |
| Villa Park | 630 | +1 630 |
| Waukegan | 224 | +1 224 |
| Waukegan | 847 | +1 847 |
| West Chicago | 312 | +1 312 |
| West Chicago | 331 | +1 331 |
| West Chicago | 630 | +1 630 |
| West Chicago | 773 | +1 773 |
| Westmont | 331 | +1 331 |
| Westmont | 630 | +1 630 |
| Wheaton | 331 | +1 331 |
| Wheaton | 630 | +1 630 |
| Wheeling | 224 | +1 224 |
| Wheeling | 847 | +1 847 |
| Wilmette | 224 | +1 224 |
| Wilmette | 847 | +1 847 |
| Woodridge | 331 | +1 331 |
| Woodridge | 630 | +1 630 |
| Woodstock | 779 | +1 779 |
| Woodstock | 815 | +1 815 |
| Zion | 224 | +1 224 |
| Zion | 847 | +1 847 |