Area Code 203-523 located in NORWALK, FAIRFIELD, CT, more detail is as below. Place NPA (Numbering Plan Area) : 203 NXX (Local Number Prefix) : 523 City : NORWALK County : FAIRFIELD State : CT (Connecticut) NXX Use Type : Landline NXX Intro Version : 1997-04-01 FIPS (Federal Information Processing Standards) : 09001 LATA (Local Access Transport Area) : 920 Rate Center : NORWALK ZIP Code Count : 2 ZIP Code Frequency : 100 ZIP Code : 06851 Other Information NPANXX : 203523 County Population : 0 Switch CLLI (Common Language Location Identifier) : HRFRCTCRDS0 MSA CBSA (Core Based Statistical Area) : Bridgeport-Stamford-Norwalk, CT MSA CBSA Code (Core Based Statistical Area) : 14860 Time Zone : Eastern (GMT -05:00) Observes Daylight Saving Time : Yes Company : TELEPORT COMMUNICATIONS GROUP - NEW YORK - CT OCN (Operating Company Number) : 7143 Coverage Area Name : NORWALK Latitude : 41.1003 Longitude : -73.4187 ‹ previous : 203-522 next › : 203-524 Telephone Number List 203-523-0000 ~ 203-523-9999