Area Code 240-366 located in WILLIAMSPORT, WASHINGTON, MD, more detail is as below. Place NPA (Numbering Plan Area) : 240 NXX (Local Number Prefix) : 366 City : WILLIAMSPORT County : WASHINGTON State : MD (Maryland) NXX Use Type : Landline NXX Intro Version : 2001-03-03 FIPS (Federal Information Processing Standards) : 24043 LATA (Local Access Transport Area) : 240 Rate Center : WILLIAMSPT ZIP Code Count : 0 ZIP Code Frequency : Most frequently occurring ZIP Code, although percentage is unknown. ZIP Code : 21795 Other Information NPANXX : 240366 County Population : 0 Switch CLLI (Common Language Location Identifier) : MNRVMDMODS1 MSA CBSA (Core Based Statistical Area) : Hagerstown-Martinsburg, MD-WV MSA CBSA Code (Core Based Statistical Area) : 25180 Time Zone : Eastern (GMT -05:00) Observes Daylight Saving Time : Yes Overlay : L Company : AT&T LOCAL OCN (Operating Company Number) : 7421 Coverage Area Name : WILLIAMSPORT Latitude : 39.5989 Longitude : -77.8245 ‹ previous : 240-365 next › : 240-367 Telephone Number List 240-366-0000 ~ 240-366-9999