Local Calling Guide

Area code/prefix search

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

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NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
312-277 A BNSVILDGDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-278 A CHCGILGMDS7  6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-278 0   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-278 1   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-278 2   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-278 3   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-278 4   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-278 5   6529 T-MOBILE USA, INC. 358   2021-09-17   
312-278 6   9329 ILLINOIS BELL TEL CO 358   2000-09-28   
312-278 7   984E BANDWIDTH.COM CLEC, LLC - IL 358   2011-09-25   
312-278 8   9329 ILLINOIS BELL TEL CO 358   2000-09-28   
312-278 9   624H ONVOY SPECTRUM, LLC 358   2022-06-16   
312-281 A   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-281 0   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-281 1   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-281 2   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-281 3   9329 ILLINOIS BELL TEL CO 358   2000-09-01   
312-281 4   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-281 5   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-281 6   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-281 7   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-281 8   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-281 9   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-283 A   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-283 0   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-283 1   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-283 2   829J PAETEC ITEL, LLC 358   2008-10-22   
312-283 3   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-283 4   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-283 5   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-283 6   732J NUSO, LLC 358   2025-06-02   
312-283 7   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358      
312-283 8   984E BANDWIDTH.COM CLEC, LLC - IL 358      
312-283 9   6333 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 358   2025-09-25   
312-285 A ELGNILOTGT5  6529 T-MOBILE USA, INC. 358      
312-285 0   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358   2006-12-09   
312-285 1   6333 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 358   2010-10-02   
312-285 2   516C AT&T CORP. 358   2005-05-09   
312-285 3   6529 T-MOBILE USA, INC. 358      
312-285 4   6529 T-MOBILE USA, INC. 358      
312-285 5   6529 T-MOBILE USA, INC. 358      
312-285 6   6529 T-MOBILE USA, INC. 358      
312-285 7   6529 T-MOBILE USA, INC. 358      
312-285 8   6529 T-MOBILE USA, INC. 358      
312-285 9   6529 T-MOBILE USA, INC. 358      
312-288 A BNSVILDGDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-288 0   7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-288 1   6333 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 358   2010-07-08   
312-288 2   7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      
312-288 3   7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358      

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Last updated: Thu, 29 Jan 2026 14:35:03 UTC

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