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: 539

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
443-539 A Columbia MD   829J PAETEC ITEL, LLC 238   2025-04-01   
443-539 0 Columbia MD   829J PAETEC ITEL, LLC 238      
443-539 1 Columbia MD   829J PAETEC ITEL, LLC 238      
443-539 2 Columbia MD   829J PAETEC ITEL, LLC 238      
443-539 3 Columbia MD   829J PAETEC ITEL, LLC 238      
443-539 4 Columbia MD   829J PAETEC ITEL, LLC 238   2006-08-15   
443-539 5 Columbia MD   7228 MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 238   2008-10-01   
443-539 6 Columbia MD   6395 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 238   2011-10-28   
443-539 7 Columbia MD   6119 LEVEL 3 COMMUNICATIONS, LLC - MD 238   2010-02-15   
443-539 8 Columbia MD   6119 LEVEL 3 COMMUNICATIONS, LLC - MD 238   2008-02-13   
443-539 9 Columbia MD   829J PAETEC ITEL, LLC 238      

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

Sponsored by: Execulink Telecom

Like this site? We accept donations via PayPal.