OAK FOR SO — IL
Data last updated: March 10, 2026
Area Codes
Top Carriers
| Carrier | OCN | NXX Count |
|---|---|---|
| NEW CINGULAR WIRELESS PCS, LLC - IL | 6534 | 21 |
| PEERLESS NETWORK OF ILLINOIS, LLC - IL | 063E | 1 |
| ONVOY, LLC | 224C | 1 |
| TON80 COMMUNICATIONS, LLC | 516J | 1 |
| LEVEL 3 COMMUNICATIONS, LLC - IL | 6115 | 1 |