Area Code +1-312-(2021000...2021999) located in Chicago, Illinois (IL), more detail is as below. Place International Dialing Code : 1 International Prefix : 011 National Prefix : 1 National Destination Code : 312 Subscriber Number From : 2021000 Subscriber Number To : 2021999 National Destination Code Length : 3 Uses National Destination Code : Yes National Significant Number Length : 10 Number Type : G (Geographic Land Line, Fixed Line) Carrier Name : AMERITECH ILLINOIS 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 : IL Region Name : Illinois City : Chicago Timezone : America/Chicago Coordinated Universal Time : -06:00 Daylight Saving Time : Yes National Significant Number Minimum Length : 10 Latitude : 41.8800 Longitude : -87.6400 ‹ previous : +1-312-(2020000...2020999) next › : +1-312-(2022000...2022999) Dialling Instructions For trunk calls: 0 312 2021000 (Trunk Code + National Destination Code + Subscriber Number) For international calls: 011 1 312 2021000 (International Prefix + International Dailing Code +National Destination Code + Subscriber Number) Telephone Number List 2021000 ~ 2021999 (Count: 1,000) Example: +1-312-2021000 / 0111-312-2021000 (1312-2021000 / 1-312-2021000) +1-312-2021001 / 0111-312-2021001 (1312-2021001 / 1-312-2021001) +1-312-2021002 / 0111-312-2021002 (1312-2021002 / 1-312-2021002) +1-312-2021003 / 0111-312-2021003 (1312-2021003 / 1-312-2021003) +1-312-2021004 / 0111-312-2021004 (1312-2021004 / 1-312-2021004) ...+1-312-xxxxxxx / 0111-312-xxxxxxx (1312-xxxxxxx / 1-312-xxxxxxx) ...+1-312-2021995 / 0111-312-2021995 (1312-2021995 / 1-312-2021995) +1-312-2021996 / 0111-312-2021996 (1312-2021996 / 1-312-2021996) +1-312-2021997 / 0111-312-2021997 (1312-2021997 / 1-312-2021997) +1-312-2021998 / 0111-312-2021998 (1312-2021998 / 1-312-2021998) +1-312-2021999 / 0111-312-2021999 (1312-2021999 / 1-312-2021999)