312 S Jackson St Jackson Mi. Area code 312 is located in Illinois. A 312 area code phon
Area code 312 is located in Illinois. A 312 area code phone number is a telephone number associated with the downtown Chicago area, including parts of its central business district. No credit card required! 5 days ago ยท The largest city it serves is Chicago. Find out where 312 area code zone from, which states, counties and cities it covers. Report includes demographic information for 312 in Chicago, IL. Get the area’s map, cities covered, current time, prefixes, and dialing instructions. Get the most exact information on time zones here. Where is Area Code 312? Area code (312) is in the state of IL. It covers roughly 7,859,286 unique phone numbers and 2,790,102 individuals near the cities of Chicago, Wheeling, and Hinsdale. The 312 area code serves Chicago, Willowbrook, Elgin, Arlington Heights, Naperville, covering 23 ZIP codes in 4 counties.