Area Code 240-423 located in SILVER SPRING, MONTGOMERY, MD, more detail is as below. Place NPA (Numbering Plan Area) : 240 NXX (Local Number Prefix) : 423 City : SILVER SPRING County : MONTGOMERY State : MD (Maryland) NXX Use Type : Wireless NXX Intro Version : 2001-10-31 FIPS (Federal Information Processing Standards) : 24031 LATA (Local Access Transport Area) : 236 Rate Center : WSHNGTNZN3 ZIP Code Count : 0 ZIP Code Frequency : Most frequently occurring ZIP Code, although percentage is unknown. ZIP Code : 20901 Other Information NPANXX : 240423 County Population : 0 Switch CLLI (Common Language Location Identifier) : BTVLMD12CM1 MSA CBSA (Core Based Statistical Area) : Washington-Arlington-Alexandria, DC-VA-MD-WV MSA CBSA Code (Core Based Statistical Area) : 47900 Time Zone : Eastern (GMT -05:00) Observes Daylight Saving Time : Yes Overlay : L Company : OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC OCN (Operating Company Number) : 6855 Coverage Area Name : SILVER SPRING Latitude : 39.0115 Longitude : -77.0405 ‹ previous : 240-423 next › : 240-424 Telephone Number List 240-423-0000 ~ 240-423-9999