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: 231 [Rate centres in NPA 231] [Dial plan for NPA 231]

NXX: 370

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
231-370 A Muskegon MI GDRPMIBL31Z  2964 OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 348      
231-370 0 Muskegon MI GDRPMIBL31Z  5562 METROPCS, INC. 348   2021-11-06   
231-370 1 Muskegon MI MSKGMIXKX1X  543C ONVOY, LLCV - MI 348   2023-08-01   
231-370 2 Muskegon MI MSKGMIXKX1X  543C ONVOY, LLCV - MI 348   2023-08-01   
231-370 3 Muskegon MI BRSPMI09AMD  490J DISH WIRELESS, LLC 348   2023-06-25   
231-370 5 Muskegon MI GDRPMIBL04Z  543C ONVOY, LLCV - MI 348   2021-11-15   
231-370 6 Muskegon MI GDRPMIBL04Z  543C ONVOY, LLCV - MI 348   2021-11-15   
231-370 7 Muskegon MI GDRPMIBL04Z  543C ONVOY, LLCV - MI 348   2021-11-15   
231-370 8 Muskegon MI GDRPMIBL31Z  2964 OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 348   2021-11-05   
231-370 9 Muskegon MI GDRPMIBL31Z  2964 OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 348   2021-11-05   

Last updated: Wed, 18 Jun 2025 02:30:00 UTC

Sponsored by: VoIP.ms

Like this site? We accept donations via PayPal.