Area Code 815-203 located in JOLIET, WILL, IL, more detail is as below. Place NPA (Numbering Plan Area) : 815 NXX (Local Number Prefix) : 203 City : JOLIET County : WILL State : IL (Illinois) NXX Use Type : Wireless NXX Intro Version : 1998-01-25 FIPS (Federal Information Processing Standards) : 17197 LATA (Local Access Transport Area) : 358 Rate Center : JOLIET ZIP Code Count : 0 ZIP Code Frequency : Most frequently occurring ZIP Code, although percentage is unknown. ZIP Code : 60433 Other Information NPANXX : 815203 Switch CLLI (Common Language Location Identifier) : NDTPILAMCM0 MSA CBSA (Core Based Statistical Area) : Chicago-Naperville-Joliet, IL-IN-WI MSA CBSA Code (Core Based Statistical Area) : 16980 Time Zone : Central (GMT -06:00) Observes Daylight Saving Time : Yes Company : USA MOBILITY WIRELESS, INC. OCN (Operating Company Number) : 6630 Coverage Area Name : JOLIET Latitude : 41.5279 Longitude : -88.0822 ‹ previous : 815-203 next › : 815-204 Telephone Number List 815-203-0000 ~ 815-203-9999