Area Code 301-312 located in BETHESDA, MONTGOMERY, MD, more detail is as below. Place NPA (Numbering Plan Area) : 301 NXX (Local Number Prefix) : 312 City : BETHESDA County : MONTGOMERY State : MD (Maryland) NXX Use Type : Wireless NXX Intro Version : 1997-10-11 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 : 20817 Other Information NPANXX : 301312 County Population : 0 Switch CLLI (Common Language Location Identifier) : GRNBMDAJCM1 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 : NEW CINGULAR WIRELESS PCS, LLC - DC OCN (Operating Company Number) : 4036 Coverage Area Name : OXON HILL Latitude : 38.8093 Longitude : -77.0988 ‹ previous : 301-310 next › : 301-312 Telephone Number List 301-312-0000 ~ 301-312-9999