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.

OCN: 820C INTRADO COMMUNICATIONS, LLC

NPA-NXX BLOCK Rate Centre Region Switch LATA LIR Eff date Disc date
227-281 5 Frederick MD   240   2026-11-02   
227-307 7 Washington Zone 2 MD   236   2026-09-27   
227-308 7 Washington Zone 3 MD   236   2026-09-27   
227-319 0 Washington Zone 10 MD   236   2026-10-27   
227-321 7 Washington Zone 4 MD   236   2026-10-27   
443-961 A Baltimore MD BLTMMDCHPMD  238      
443-961 0 Baltimore MD BLTMMDCHPMD  238   2015-02-13   
443-961 9 Baltimore MD BLTMMDCHPMD  238   2015-02-13   
667-547 4 Baltimore MD   238   2026-09-13   
667-548 7 Towson MD   238   2026-10-10   
667-549 9 Annapolis MD   238   2026-10-10   
667-560 0 Baltimore MD   238   2026-10-05   
667-560 1 Baltimore MD   238   2026-10-05   
667-771 0 Baltimore MD BLTMMDCHPMD  238   2016-08-20   

Last updated: Tue, 29 Sep 2026 03:00:13 UTC

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