Area Code 301-584 located in SILVER SPRING, MONTGOMERY, MD, more detail is as below. Place NPA (Numbering Plan Area) : 301 NXX (Local Number Prefix) : 584 City : SILVER SPRING County : MONTGOMERY State : MD (Maryland) NXX Use Type : Landline NXX Intro Version : 2000-06-13 FIPS (Federal Information Processing Standards) : 24031 LATA (Local Access Transport Area) : 236 Rate Center : WSHNGTNZN2 ZIP Code Count : 0 ZIP Code Frequency : Second most frequently occurring ZIP Code, although percentage is unknown. ZIP Code : 20902 Other Information NPANXX : 301584 County Population : 0 Switch CLLI (Common Language Location Identifier) : LARLMDEH00T 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 Company : BALTIMORE-WASHINGTON TELEPHONE BWT OCN (Operating Company Number) : 8697 Coverage Area Name : SILVER SPRING Latitude : 39.0827 Longitude : -77.0487 ‹ previous : 301-583 next › : 301-584 Telephone Number List 301-584-0000 ~ 301-584-9999