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: DTRTMIHGDS0

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
313-491 A Detroit Zone 4 MI 9323 MICHIGAN BELL TEL CO 340      
313-834 A Detroit Zone 4 MI 9323 MICHIGAN BELL TEL CO 340      
313-931 A Detroit Zone 4 MI 9323 MICHIGAN BELL TEL CO 340      
313-933 A Detroit Zone 4 MI 9323 MICHIGAN BELL TEL CO 340      
313-934 A Detroit Zone 4 MI 9323 MICHIGAN BELL TEL CO 340      
313-935 A Detroit Zone 4 MI 9323 MICHIGAN BELL TEL CO 340      

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

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