Real 312 — The 312 area code and Chicago-region | real312.com
One city, two codes and a ring of suburban overlay pairs — here is which code sits on which part of the Chicago region.
Start downtown. Area code 312 covers central Chicago: the Loop, the Near North Side, the Near West Side and the downtown ZIP codes 60601 through 60607. If an address sits in that zone, its numbers come from the 312 pool.
Step outside the core and you are in 773. The 773 code split away from 312 in 1996 and took the rest of the city with it, so a Chicago address that is not in the central zone is a 773 address.
Cross the city line and the pattern changes from split to overlay. DuPage County runs 630 with 331 laid over it; the north and northwest suburbs run 847 with 224; Will, Kankakee and Grundy counties run 815 with 779. In each pair, both codes serve the same streets, and local calls take ten digits.
On narrow screens, swipe or scroll the plate sideways.
Where does 708 fit? It is a separate Chicago-area code outside the 312/773 city pair. The practical point for a caller is not its exact boundary but its distinctness: a 708 number is neither a downtown 312 line nor a 773 city line, and it should not be read as one.
Beyond the metro, the rest of Illinois still answers to 618 — the state's other original 1947 code, covering everything that was not Chicago when the plan was drawn.
The lookup method, then: match the address to the zone first, then read the code. Downtown means 312; the neighbourhoods mean 773; the suburbs mean one of the three overlay pairs; and 708 stands on its own. Once you have the code, the dialling guide on this site gives the exact string for your phone.
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