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: BLTMMDCHAMD

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
410-306 9 Aberdeen MD 1958 ATX TELECOMMUNICATIONS SERVICES, LTD. 236   2003-02-25   
410-319 0 Baltimore MD 1958 ATX TELECOMMUNICATIONS SERVICES, LTD. 238   2004-02-15   
410-774 8 Crofton MD 2217 ATX TELECOMMUNICATIONS SERVICES, LTD. - MD 238   2003-02-25   
443-259 9 Columbia MD 1958 ATX TELECOMMUNICATIONS SERVICES, LTD. 238   2003-02-25   
443-341 8 Catonsville MD 1958 ATX TELECOMMUNICATIONS SERVICES, LTD. 238   2004-03-27   

Last updated: Sun, 26 Jan 2025 15:59:20 UTC

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