Area Code +1-203-(3700000...3709999) located in New Haven, Connecticut (CT), more detail is as below. Place International Dialing Code : 1 International Prefix : 011 National Prefix : 1 National Destination Code : 203 Subscriber Number From : 3700000 Subscriber Number To : 3709999 National Destination Code Length : 3 Uses National Destination Code : Yes National Significant Number Length : 10 Number Type : M (Mobile, Cellular) Carrier Name : AMERICAN MESSAGING 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 : CT Region Name : Connecticut City : New Haven Timezone : America/New_York Coordinated Universal Time : -05:00 Daylight Saving Time : Yes National Significant Number Minimum Length : 10 Latitude : 41.3000 Longitude : -72.9300 ‹ previous : +1-203-(3699000...3699999) next › : +1-203-(3710000...3719999) Dialling Instructions For trunk calls: 0 203 3700000 (Trunk Code + National Destination Code + Subscriber Number) For international calls: 011 1 203 3700000 (International Prefix + International Dailing Code +National Destination Code + Subscriber Number) Telephone Number List 3700000 ~ 3709999 (Count: 10,000) Example: +1-203-3700000 / 0111-203-3700000 (1203-3700000 / 1-203-3700000) +1-203-3700001 / 0111-203-3700001 (1203-3700001 / 1-203-3700001) +1-203-3700002 / 0111-203-3700002 (1203-3700002 / 1-203-3700002) +1-203-3700003 / 0111-203-3700003 (1203-3700003 / 1-203-3700003) +1-203-3700004 / 0111-203-3700004 (1203-3700004 / 1-203-3700004) ...+1-203-xxxxxxx / 0111-203-xxxxxxx (1203-xxxxxxx / 1-203-xxxxxxx) ...+1-203-3709995 / 0111-203-3709995 (1203-3709995 / 1-203-3709995) +1-203-3709996 / 0111-203-3709996 (1203-3709996 / 1-203-3709996) +1-203-3709997 / 0111-203-3709997 (1203-3709997 / 1-203-3709997) +1-203-3709998 / 0111-203-3709998 (1203-3709998 / 1-203-3709998) +1-203-3709999 / 0111-203-3709999 (1203-3709999 / 1-203-3709999)