Area Code 240-404 located in GAITHERSBURG, MONTGOMERY, MD, more detail is as below. Place NPA (Numbering Plan Area) : 240 NXX (Local Number Prefix) : 404 City : GAITHERSBURG County : MONTGOMERY State : MD (Maryland) NXX Use Type : Landline NXX Intro Version : 2001-06-30 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 : 240404 County Population : 0 Switch CLLI (Common Language Location Identifier) : WASHDCCZDS0 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 : XO MARYLAND, LLC OCN (Operating Company Number) : 4773 Coverage Area Name : GAITHERSBURG Latitude : 39.1431 Longitude : -77.2031 ‹ previous : 240-404 next › : 240-405 Telephone Number List 240-404-0000 ~ 240-404-9999