Area Code 301-837 located in WINDSOR MILL, BALTIMORE, MD, more detail is as below. Place NPA (Numbering Plan Area) : 301 NXX (Local Number Prefix) : 837 City : WINDSOR MILL County : BALTIMORE State : MD (Maryland) NXX Use Type : Landline NXX Intro Version : 1998-11-20 FIPS (Federal Information Processing Standards) : 24005 LATA (Local Access Transport Area) : 236 Rate Center : WSNGTNZN13 ZIP Code Count : 1 ZIP Code Frequency : 33 ZIP Code : 21244 Other Information NPANXX : 301837 County Population : 0 Switch CLLI (Common Language Location Identifier) : WASHDCINDS0 MSA CBSA (Core Based Statistical Area) : Baltimore-Towson, MD MSA CBSA Code (Core Based Statistical Area) : 12580 Time Zone : Eastern (GMT -05:00) Observes Daylight Saving Time : Yes Company : MCIMETRO ACCESS TRANSMISSION SERVICES LLC OCN (Operating Company Number) : 7229 Coverage Area Name : HYATTSVILLE Latitude : 38.9550 Longitude : -76.9976 ‹ previous : 301-837 next › : 301-837 Telephone Number List 301-837-0000 ~ 301-837-9999