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: 573 [Rate centres in NPA 573] [Dial plan for NPA 573]

NXX: 503

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
573-503 A Middletown MO STLSMOPLDS4  4932 LEVEL 3 COMMUNICATIONS, LLC - MO 520      
573-503 0 Middletown MO STLSMOWQ8MD  073H TELNYX LLC 520   2020-08-02   
573-503 1 Middletown MO STLSMO05RMD  993E BANDWIDTH.COM CLEC, LLC - MO 520   2021-09-18   
573-503 4 Middletown MO STLSMOPLDS4  4932 LEVEL 3 COMMUNICATIONS, LLC - MO 520   2006-06-30   
573-503 8 Middletown MO STLSMO05XMX  624H ONVOY SPECTRUM, LLC 520   2024-03-23   

Last updated: Sun, 27 Apr 2025 12:48:38 UTC

Sponsored by: VoIP Much Phone Company

Like this site? We accept donations via PayPal.