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.
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Switch: CTVLMDCTDS0

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
410-455 A Catonsville MD 9212 VERIZON MARYLAND, INC. 238      
410-719 A Catonsville MD 9212 VERIZON MARYLAND, INC. 238      
410-744 A Catonsville MD 9212 VERIZON MARYLAND, INC. 238      
410-747 A Catonsville MD 9212 VERIZON MARYLAND, INC. 238      
410-788 A Catonsville MD 9212 VERIZON MARYLAND, INC. 238      
410-869 A Catonsville MD 9212 VERIZON MARYLAND, INC. 238      
443-612 A Catonsville MD 9212 VERIZON MARYLAND, INC. 238      

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

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