CHICGOZN05 — IL
Data last updated: March 10, 2026
Area Codes
Top Carriers
| Carrier | OCN | NXX Count |
|---|---|---|
| ILLINOIS BELL TEL CO | 9329 | 19 |
| ONVOY, LLC | 224C | 7 |
| NEW CINGULAR WIRELESS PCS, LLC - IL | 6534 | 5 |
| MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | 5 |
| PAETEC ITEL, LLC | 829J | 4 |