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.

Gary, SD

NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
605-272 A CLLKSDXADS0  1651 INTERSTATE TELECOM COOP, INC. - SD 640      

Last updated: Thu, 29 Jan 2026 14:35:03 UTC

Sponsored by: Execulink Telecom

Like this site? We accept donations via PayPal.