Illinois · Central Time
773 Area Code
Area code 773 is in Illinois, serving the City of Chicago outside the downtown 312 area. It is in the Central Time zone. It shares its territory with overlay code 872, so 10-digit dialing is required.
Last updated October 1, 2026 · Source: NANPA
Where is the 773 area code?
773 is a Illinois area code covering the City of Chicago outside the downtown 312 area. In the wider directory it sits in the Midwest region.
Cities in the 773 area code
Counties served by 773
Cook County.
773 overlay codes and dialing
The 773 territory is covered by an overlay of 2 area codes: 773, 872. All of them serve the same geographic area, and the original code is 773. Because more than one code covers the same ground, 10-digit dialing is mandatory — you must dial the area code for every local call. New phone lines may be assigned any of these codes.
History of the 773 area code
773 went into service on October 12, 1996, created when it was split from 312. It serves Chicago and the surrounding part of Illinois, and today shares its territory with overlay code 872. For how codes are created, split, and overlaid, see how area codes work.
Is 773 a scam or spam risk?
773 is a legitimate geographic area code, not a premium or toll line, so a call from it costs you nothing extra. That said, scammers frequently spoof real local area codes to look familiar on caller ID. A genuine 773 number on your screen is no guarantee the caller is in Chicago, IL or trustworthy. See spam & scam-risk area codes for how spoofing works and how to respond.
Other Illinois area codes
Explore more
See every code in Illinois, compare codes across the Midwest region, or view all Central Time codes. You can also browse the 7XX block or the complete numeric list of US area codes.
New to how this all works? Start with how area codes work, then read up on overlays, 10-digit dialing, and spam & scam-risk codes. To check another number, use the area code lookup tool.
Quick answers
773 area code FAQ
Where is the 773 area code?
The 773 area code is in Illinois, covering the City of Chicago outside the downtown 312 area, in the Midwest region.
What cities are in the 773 area code?
Cities in the 773 area code include Chicago.
What time zone is 773 in?
773 is in the Central Time zone.
What is the overlay for the 773 area code?
773 shares its territory with 872. Both codes (773, 872) serve the same area, so 10-digit dialing is required for every call.
When did the 773 area code start?
773 went into service on October 12, 1996.
Do I have to dial 10 digits for 773?
Yes. Because 773 is an overlay area, you must dial the full 10-digit number (area code + 7 digits) for every call.
Is 773 a toll-free or premium code?
No. 773 is a standard geographic area code, so calling it costs the same as any local or long-distance call on your plan. Toll-free calls use 800, 888, 877, 866, 855, 844 or 833.