Area Code 231-312 located in FRANKFORT, BENZIE, MI, more detail is as below. Place NPA (Numbering Plan Area) : 231 NXX (Local Number Prefix) : 312 City : FRANKFORT County : BENZIE State : MI (Michigan) NXX Use Type : Landline NXX Intro Version : 2001-03-03 FIPS (Federal Information Processing Standards) : 26019 LATA (Local Access Transport Area) : 348 Rate Center : FRANKFORT ZIP Code Count : 0 ZIP Code Frequency : Most frequently occurring ZIP Code, although percentage is unknown. ZIP Code : 49635 Other Information NPANXX : 231312 County Population : 0 Switch CLLI (Common Language Location Identifier) : GDRQMIFOCA0 MSA CBSA (Core Based Statistical Area) : Traverse City, MI MSA CBSA Code (Core Based Statistical Area) : 45900 Time Zone : Eastern (GMT -05:00) Observes Daylight Saving Time : Yes Company : TELNET WORLDWIDE, INC. OCN (Operating Company Number) : 4632 Coverage Area Name : FRANKFORT Latitude : 44.6326 Longitude : -86.2464 ‹ previous : 231-309 next › : 231-313 Telephone Number List 231-312-0000 ~ 231-312-9999