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.

NPA: 443 [Rate centres in NPA 443] [Dial plan for NPA 443]

NXX: 821

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
443-821 A Westminster MD BLTMMDCH40Z  5562 METROPCS, INC. 238      
443-821 0 Westminster MD   071F BANDWIDTH.COM CLEC, LLC - MD 238   2010-10-28   
443-821 1 Westminster MD   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2010-10-11   
443-821 2 Westminster MD   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2010-10-27   
443-821 3 Westminster MD   318J COMCAST IP PHONE, LLC 238   2010-12-10   
443-821 4 Westminster MD   6395 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 238   2011-02-03   
443-821 5 Westminster MD   6395 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 238   2011-02-03   
443-821 6 Westminster MD   6395 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 238   2011-09-27   
443-821 7 Westminster MD   071F BANDWIDTH.COM CLEC, LLC - MD 238   2011-06-02   
443-821 8 Westminster MD   5562 METROPCS, INC. 238   2010-09-06   
443-821 9 Westminster MD   5562 METROPCS, INC. 238   2010-09-06   

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

Sponsored by: Execulink Telecom

Like this site? We accept donations via PayPal.