Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
  • Effective date searches are available only for US area codes. Our sources for non-US NPA-NXX data do not provide this information.
  • If you want to search an entire area code regardless of activity, leave both the next and past days fields set to zero.

Switch: CHCGILWB55T

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
312-591 A Chicago Zone 01-Wabash IL 9329 ILLINOIS BELL TEL CO 358      
630-591 A Chicago Zone 01-Wabash IL 9329 ILLINOIS BELL TEL CO 358      
708-591 A Chicago Zone 01-Wabash IL 9329 ILLINOIS BELL TEL CO 358      
773-591 A Chicago Zone 01-Wabash IL 9329 ILLINOIS BELL TEL CO 358      
847-591 A Chicago Zone 01-Wabash IL 9329 ILLINOIS BELL TEL CO 358      

Last updated: Thu, 20 Nov 2025 13:34:34 UTC

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