Area Code 240-223 located in BETHESDA, MONTGOMERY, MD, more detail is as below. Place NPA (Numbering Plan Area) : 240 NXX (Local Number Prefix) : 223 City : BETHESDA County : MONTGOMERY State : MD (Maryland) NXX Use Type : Landline NXX Intro Version : 1999-02-27 FIPS (Federal Information Processing Standards) : 24031 LATA (Local Access Transport Area) : 236 Rate Center : WSHNGTNZN2 ZIP Code Count : 1 ZIP Code Frequency : 100 ZIP Code : 20814 Other Information NPANXX : 240223 County Population : 0 Switch CLLI (Common Language Location Identifier) : WASHDCRKDS3 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 : ALLEGIANCE TELECOM, INC. - MD OCN (Operating Company Number) : 8992 Coverage Area Name : MOUNT RAINIER Latitude : 38.9047 Longitude : -77.0281 ‹ previous : 240-222 next › : 240-224 Telephone Number List 240-223-0000 ~ 240-223-9999