Area Code 231-237 located in CHARLEVOIX, CHARLEVOIX, MI, more detail is as below. Place NPA (Numbering Plan Area) : 231 NXX (Local Number Prefix) : 237 City : CHARLEVOIX County : CHARLEVOIX State : MI (Michigan) NXX Use Type : Landline NXX Intro Version : 1999-07-22 FIPS (Federal Information Processing Standards) : 26029 LATA (Local Access Transport Area) : 348 Rate Center : CHARLEVOIX ZIP Code Count : 507 ZIP Code Frequency : 96 ZIP Code : 49720 Other Information NPANXX : 231237 County Population : 0 Switch CLLI (Common Language Location Identifier) : CHVXMIMNRS0 Time Zone : Eastern (GMT -05:00) Observes Daylight Saving Time : Yes Company : AMERITECH MICHIGAN OCN (Operating Company Number) : 9323 Coverage Area Name : CHARLEVOIX Latitude : 45.3141 Longitude : -85.2632 ‹ previous : 231-237 next › : 231-238 Telephone Number List 231-237-0000 ~ 231-237-9999