Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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Chicago Zone 01-Monroe, IL

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NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
312-666 A CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-710 A CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-733 A CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-738 A CHCGILMODS0  9329 ILLINOIS BELL TEL CO 358      
312-743 A CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-743 0   9329 ILLINOIS BELL TEL CO 358      
312-743 1   9329 ILLINOIS BELL TEL CO 358      
312-743 2   9329 ILLINOIS BELL TEL CO 358      
312-743 3   9329 ILLINOIS BELL TEL CO 358      
312-743 4   9329 ILLINOIS BELL TEL CO 358      
312-743 5   9329 ILLINOIS BELL TEL CO 358      
312-743 6   9329 ILLINOIS BELL TEL CO 358      
312-743 7   9329 ILLINOIS BELL TEL CO 358      
312-743 8   9329 ILLINOIS BELL TEL CO 358      
312-743 9   9329 ILLINOIS BELL TEL CO 358      
312-746 A CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-829 A CHCGILMODS0  9329 ILLINOIS BELL TEL CO 358      
312-850 A CHCGILMODS0  9329 ILLINOIS BELL TEL CO 358      
312-864 A CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-894 A BNSVILDGDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-894 0 BNSVILDGDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-894 1 BNSVILDGDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-894 2 BNSVILDGDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-894 3 BNSVILDGDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-894 4 BNSVILDGDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-894 5 BNSVILDGDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-894 6 BNSVILDGDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-894 7 BNSVILDGDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-894 8 BNSVILDGDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-894 9 BURGILAHGT3  6534 NEW CINGULAR WIRELESS PCS, LLC - IL 358   2011-08-07   
312-942 A CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-996 A CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-997 A CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-997 0 CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-997 1 CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-997 2 CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-997 3 CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-997 4 CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-997 5 CHCGILGMDS7  6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358   2014-05-03   
312-997 6 CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-997 7 CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-997 8 CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      
312-997 9 CHCGILMODS1  9329 ILLINOIS BELL TEL CO 358      

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Last updated: Tue, 16 Jun 2026 00:09:45 UTC

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