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.

Switch: BSMRMOPERS0

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
573-734 A Bismarck MO 9533 SOUTHWESTERN BELL 520      
573-734 1 Bismarck MO 9533 SOUTHWESTERN BELL 520      
573-734 2 Bismarck MO 9533 SOUTHWESTERN BELL 520      
573-734 6 Bismarck MO 9533 SOUTHWESTERN BELL 520      

Last updated: Sat, 15 Nov 2025 03:38:44 UTC

Sponsored by: VoIP.ms

Like this site? We accept donations via PayPal.