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-NXX BLOCK Rate Centre Region Switch LATA LIR Eff date Disc date
970-303 2 Windsor CO   656   2025-10-18   
970-303 4 Windsor CO   656   2025-10-18   
970-303 5 Windsor CO   656   2025-10-18   
970-303 6 Windsor CO   656   2025-10-18   
970-303 7 Windsor CO   656   2025-10-18   
983-220 A Denver CO   656   2025-09-11   
983-220 2 Denver CO   656   2025-09-11   
983-220 3 Denver CO   656   2025-09-11   

Last updated: Tue, 07 Oct 2025 16:47:53 UTC

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