Area Code 240-306 located in GAITHERSBURG, MONTGOMERY, MD, more detail is as below. Place NPA (Numbering Plan Area) : 240 NXX (Local Number Prefix) : 306 City : GAITHERSBURG 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 : GAITHERSBG ZIP Code Count : 0 ZIP Code Frequency : Most frequently occurring ZIP Code, although percentage is unknown. ZIP Code : 20877 Other Information NPANXX : 240306 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 : GAITHERSBURG Latitude : 39.1431 Longitude : -77.2031 ‹ previous : 240-306 next › : 240-307 Telephone Number List 240-306-0000 ~ 240-306-9999