Area Code 303-231 located in GOLDEN, JEFFERSON, CO, more detail is as below. Place NPA (Numbering Plan Area) : 303 NXX (Local Number Prefix) : 231 City : GOLDEN County : JEFFERSON State : CO (Colorado) NXX Use Type : Landline NXX Intro Version : 1994-02-04 FIPS (Federal Information Processing Standards) : 08059 LATA (Local Access Transport Area) : 656 Rate Center : DENVER ZIP Code Count : 20 ZIP Code Frequency : 9 ZIP Code : 80401 Other Information NPANXX : 303231 County Population : 0 Switch CLLI (Common Language Location Identifier) : LKWDCOMADS0 MSA CBSA (Core Based Statistical Area) : Denver-Aurora, CO MSA CBSA Code (Core Based Statistical Area) : 19740 Time Zone : Mountain (GMT -07:00) Observes Daylight Saving Time : Yes Company : QWEST CORPORATION OCN (Operating Company Number) : 9636 Coverage Area Name : DENVER Latitude : 39.7375 Longitude : -105.0792 ‹ previous : 303-231 next › : 303-231 Telephone Number List 303-231-0000 ~ 303-231-9999