Area Code 423-557 located in PHILADELPHIA, LOUDON, TN, more detail is as below. Place NPA (Numbering Plan Area) : 423 NXX (Local Number Prefix) : 557 City : PHILADELPHIA County : LOUDON State : TN (Tennessee) NXX Use Type : Wireless NXX Intro Version : 2005-03-27 FIPS (Federal Information Processing Standards) : 47105 LATA (Local Access Transport Area) : 956 Rate Center : JOHNSON CY ZIP Code Count : 0 ZIP Code Frequency : Most frequently occurring ZIP Code, although percentage is unknown. ZIP Code : 37846 Other Information NPANXX : 423557 County Population : 0 Switch CLLI (Common Language Location Identifier) : JHCYTNDD2MD MSA CBSA (Core Based Statistical Area) : Knoxville, TN MSA CBSA Code (Core Based Statistical Area) : 28940 Time Zone : Eastern (GMT -05:00) Observes Daylight Saving Time : Yes Company : SUNCOM DBA T-MOBILE USA OCN (Operating Company Number) : 8645 Coverage Area Name : SWEETWATER Latitude : 35.6084 Longitude : -84.4651 ‹ previous : 423-557 next › : 423-558 Telephone Number List 423-557-0000 ~ 423-557-9999