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: 603 [Rate centres in NPA 603] [Dial plan for NPA 603]

NXX: 390

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
603-390 A Jefferson NH MNCHNHACDS0  7778 MCIMETRO ACCESS TRANSMISSION SERVICES LLC - NH 122      
603-390 2 Jefferson NH   145J TERRA NOVA TELECOM INC. 122   2023-11-11   
603-390 6 Jefferson NH MNCHNHAC7MD  145J TERRA NOVA TELECOM INC. 122   2024-10-11   
603-390 9 Jefferson NH MNCHNHACDS0  7778 MCIMETRO ACCESS TRANSMISSION SERVICES LLC - NH 122      

Last updated: Sat, 05 Apr 2025 03:03:23 UTC

Sponsored by: Callcentric - VoIP Internet phone service

Like this site? We accept donations via PayPal.