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: 540

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
443-540 A Baltimore MD CLMAMDORGT0  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238      

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

Sponsored by: VoIP Much Phone Company

Like this site? We accept donations via PayPal.