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: CHCGILFRDS1

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
312-214 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-223 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-244 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-309 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-338 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-384 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-394 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-409 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-424 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-458 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-460 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-574 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-634 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-683 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-696 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-793 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-814 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-862 A Chicago Zone 01-Calumet IL 9329 ILLINOIS BELL TEL CO 358      
312-904 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-905 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      
312-992 A Chicago Zone 01-Franklin IL 9329 ILLINOIS BELL TEL CO 358      

Last updated: Tue, 13 Jan 2026 21:50:02 UTC

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