CHICGOZN11 — IL
Data last updated: March 10, 2026
Area Codes
Top Carriers
| Carrier | OCN | NXX Count |
|---|---|---|
| ILLINOIS BELL TEL CO | 9329 | 7 |
| LEVEL 3 COMMUNICATIONS, LLC - IL | 6115 | 4 |
| MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | 3 |
| MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL | 7196 | 2 |
| PAETEC ITEL, LLC | 829J | 2 |