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.

Knox City, MO

NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
660-434 A HRLDMOXADS0  1914 MARK TWAIN RURAL TEL. CO. 524      

Last updated: Wed, 04 Mar 2026 03:00:52 UTC

Sponsored by: VoIP Much Phone Company

Like this site? We accept donations via PayPal.