Area Code 240-277 located in BETHESDA, MONTGOMERY, MD, more detail is as below. Place NPA (Numbering Plan Area) : 240 NXX (Local Number Prefix) : 277 City : BETHESDA County : MONTGOMERY State : MD (Maryland) NXX Use Type : Wireless NXX Intro Version : 2003-02-09 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 : 240277 County Population : 0 Switch CLLI (Common Language Location Identifier) : BTVLMDCKCM5 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 : SPRINT SPECTRUM L.P. OCN (Operating Company Number) : 6664 Coverage Area Name : BETHESDA Latitude : 38.9858 Longitude : -77.1065 ‹ previous : 240-276 next › : 240-277 Telephone Number List 240-277-0000 ~ 240-277-9999