Area Code 312-371 located in CHICAGO, COOK, IL, more detail is as below. Place NPA (Numbering Plan Area) : 312 NXX (Local Number Prefix) : 371 City : CHICAGO County : COOK State : IL (Illinois) NXX Use Type : Wireless NXX Intro Version : 1998-01-25 FIPS (Federal Information Processing Standards) : 17031 LATA (Local Access Transport Area) : 358 Rate Center : CHICGOZN01 ZIP Code Count : 1 ZIP Code Frequency : 25 ZIP Code : 60622 Other Information NPANXX : 312371 County Population : 0 Switch CLLI (Common Language Location Identifier) : BRDVILBOCM0 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 : SPRINT SPECTRUM L.P. OCN (Operating Company Number) : 6664 Coverage Area Name : CHICAGO Latitude : 41.7465 Longitude : -87.8040 ‹ previous : 312-370 next › : 312-371 Telephone Number List 312-371-0000 ~ 312-371-9999