Area Code +1-301-(2120000...2120999) located in Rockville, Maryland (MD), more detail is as below. Place International Dialing Code : 1 International Prefix : 011 National Prefix : 1 National Destination Code : 301 Subscriber Number From : 2120000 Subscriber Number To : 2120999 National Destination Code Length : 3 Uses National Destination Code : Yes National Significant Number Length : 10 Number Type : M (Mobile, Cellular) Carrier Name : METRO PCS INC. Click here to buy United States Area Code Database Other Information Language Code : en (English) Country Number : 840 (United States) Country Code : US (United States) Region Code : MD Region Name : Maryland City : Rockville Timezone : America/New_York Coordinated Universal Time : -05:00 Daylight Saving Time : Yes National Significant Number Minimum Length : 10 Latitude : 39.0900 Longitude : -77.1600 ‹ previous : +1-301-(2100000...2109999) next › : +1-301-(2121000...2121999) Dialling Instructions For trunk calls: 0 301 2120000 (Trunk Code + National Destination Code + Subscriber Number) For international calls: 011 1 301 2120000 (International Prefix + International Dailing Code +National Destination Code + Subscriber Number) Telephone Number List 2120000 ~ 2120999 (Count: 1,000) Example: +1-301-2120000 / 0111-301-2120000 (1301-2120000 / 1-301-2120000) +1-301-2120001 / 0111-301-2120001 (1301-2120001 / 1-301-2120001) +1-301-2120002 / 0111-301-2120002 (1301-2120002 / 1-301-2120002) +1-301-2120003 / 0111-301-2120003 (1301-2120003 / 1-301-2120003) +1-301-2120004 / 0111-301-2120004 (1301-2120004 / 1-301-2120004) ...+1-301-xxxxxxx / 0111-301-xxxxxxx (1301-xxxxxxx / 1-301-xxxxxxx) ...+1-301-2120995 / 0111-301-2120995 (1301-2120995 / 1-301-2120995) +1-301-2120996 / 0111-301-2120996 (1301-2120996 / 1-301-2120996) +1-301-2120997 / 0111-301-2120997 (1301-2120997 / 1-301-2120997) +1-301-2120998 / 0111-301-2120998 (1301-2120998 / 1-301-2120998) +1-301-2120999 / 0111-301-2120999 (1301-2120999 / 1-301-2120999)