MONMOUTH — IL
Data last updated: March 10, 2026
Area Codes
Top Carriers
| Carrier | OCN | NXX Count |
|---|---|---|
| CITIZENS TELECOM CO ILLINOIS-FRONTIER CITIZENS -IL | 1183 | 2 |
| MTC COMMUNICATIONS, INC. - IL | 342F | 1 |
| IP HORIZON LLC | 515J | 1 |
| LEVEL 3 COMMUNICATIONS, LLC - IL | 6115 | 1 |
| CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 6333 | 1 |