Area Code 406-437 located in HELENA, LEWIS AND CLARK, MT, more detail is as below. Place NPA (Numbering Plan Area) : 406 NXX (Local Number Prefix) : 437 City : HELENA County : LEWIS AND CLARK State : MT (Montana) NXX Use Type : Landline NXX Intro Version : 2004-12-13 FIPS (Federal Information Processing Standards) : 30049 LATA (Local Access Transport Area) : 648 Rate Center : HELENA ZIP Code Count : 0 ZIP Code Frequency : Most frequently occurring ZIP Code, although percentage is unknown. ZIP Code : 59601 Other Information NPANXX : 406437 Switch CLLI (Common Language Location Identifier) : HLNAMTMAMM0 MSA CBSA (Core Based Statistical Area) : Helena, MT MSA CBSA Code (Core Based Statistical Area) : 25740 Time Zone : Mountain (GMT -07:00) Observes Daylight Saving Time : Yes Company : MCIMETRO ACCESS TRANSMISSION SERVICES LLC OCN (Operating Company Number) : 7229 Coverage Area Name : HELENA Latitude : 46.6012 Longitude : -112.0221 ‹ previous : 406-437 next › : 406-438 Telephone Number List 406-437-0000 ~ 406-437-9999