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: 531 [Rate centres in NPA 531] [Dial plan for NPA 531]

NXX: 531

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
531-531 A South Sioux City NE SXCYIA799MD  883K AHOI LLC 630   2026-07-25   
531-531 1 South Sioux City NE SXCYIA799MD  883K AHOI LLC 630   2026-07-25   
531-531 7 South Sioux City NE   826C INTRADO COMMUNICATIONS, LLC 630   2026-10-10   

Last updated: Sat, 10 Oct 2026 15:24:20 UTC

Sponsored by: LES.NET

Like this site? We accept donations via PayPal.