Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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NPA: 815 [Rate centres in NPA 815] [Dial plan for NPA 815]

NXX: 788

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
815-788 A Crystal Lake IL CRLKILCKDS0  9329 ILLINOIS BELL TEL CO 358      
815-788 0 Crystal Lake IL   9329 ILLINOIS BELL TEL CO 358      
815-788 1 Crystal Lake IL   9329 ILLINOIS BELL TEL CO 358      
815-788 2 Crystal Lake IL   9329 ILLINOIS BELL TEL CO 358      
815-788 3 Crystal Lake IL   9329 ILLINOIS BELL TEL CO 358      
815-788 4 Crystal Lake IL   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358   2006-02-11   
815-788 5 Crystal Lake IL   9329 ILLINOIS BELL TEL CO 358      
815-788 6 Crystal Lake IL   6115 LEVEL 3 COMMUNICATIONS, LLC - IL 358   2008-05-12   
815-788 7 Crystal Lake IL   9329 ILLINOIS BELL TEL CO 358      
815-788 8 Crystal Lake IL   9329 ILLINOIS BELL TEL CO 358      
815-788 9 Crystal Lake IL   9329 ILLINOIS BELL TEL CO 358      

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

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