Area Code 231-424 located in CUSTER, MASON, MI, more detail is as below. Place NPA (Numbering Plan Area) : 231 NXX (Local Number Prefix) : 424 City : CUSTER County : MASON State : MI (Michigan) NXX Use Type : Landline NXX Intro Version : 2005-06-25 FIPS (Federal Information Processing Standards) : 26105 LATA (Local Access Transport Area) : 348 Rate Center : CARR ZIP Code Count : 0 ZIP Code Frequency : Second most frequently occurring ZIP Code, although percentage is unknown. ZIP Code : 49405 Other Information NPANXX : 231424 County Population : 0 Switch CLLI (Common Language Location Identifier) : GDRPMIBLXTZ Time Zone : Eastern (GMT -05:00) Observes Daylight Saving Time : Yes Company : ACD TELECOM, INC. - MI OCN (Operating Company Number) : 3535 Coverage Area Name : BRANCH Latitude : 43.8515 Longitude : -86.0664 ‹ previous : 231-423 next › : 231-424 Telephone Number List 231-424-0000 ~ 231-424-9999