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: CLMAMDNIDS1

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
443-273 A Reisterstown MD 7325 TELEPORT COMMUNICATIONS AMERICA, LLC - MD 238      
443-364 A Ellicott City MD 7325 TELEPORT COMMUNICATIONS AMERICA, LLC - MD 238      
443-620 A Waterloo MD 7325 TELEPORT COMMUNICATIONS AMERICA, LLC - MD 238      
443-733 A Waterloo MD 7325 TELEPORT COMMUNICATIONS AMERICA, LLC - MD 238      
443-886 A Cockeysville MD 7325 TELEPORT COMMUNICATIONS AMERICA, LLC - MD 238      
443-920 A Sykesville MD 7325 TELEPORT COMMUNICATIONS AMERICA, LLC - MD 238      
443-933 A Cockeysville MD 7325 TELEPORT COMMUNICATIONS AMERICA, LLC - MD 238      
443-942 A Severna Park MD 7325 TELEPORT COMMUNICATIONS AMERICA, LLC - MD 238      
667-786 A Columbia MD 7325 TELEPORT COMMUNICATIONS AMERICA, LLC - MD 238      

Last updated: Thu, 01 Jan 2026 03:59:49 UTC

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