Illinois Area Codes

About Area Codes in Illinois

Illinois (IL) is the The Prairie State, located in the Midwest region of the United States. With a 2023 population of 12,549,689 residents, Illinois is served by 13 active area codes. The state capital is Springfield and the largest city is Chicago.Illinois's official motto is "State Sovereignty, National Union."

Area code assignments in Illinois follow the North American Numbering Plan (NANP), which has been in effect since 1947. As the state's population and demand for phone numbers grew — driven by the rise of cell phones, fax machines, pagers, and VoIP lines — regulators either split existing area codes geographically or added overlay codes that share the same territory. That's why Illinois now has 13 codes: 217, 224, 309, 312, 331, 618, 630, 708, 773, 779, 815, 847, 872.

When you receive a call from a Illinois number, the area code tells you only where the number was originally assigned. Because of Local Number Portability (LNP), which took effect in 2003, callers can keep their phone numbers even when moving across state lines. So while a 217 number was once assigned in Illinois, the person calling you could be anywhere in the US today.

Time zones in Illinois

Illinois observes the Central time zone. Daylight Saving Time is observed from the second Sunday in March through the first Sunday in November, when clocks shift forward by one hour. When you call a Illinois number from outside the state, double-check the local time above each area code detail page to avoid calling at unreasonable hours.

Phone number format in Illinois

All Illinois phone numbers follow the standard 10-digit NANP format: (NPA) NXX-XXXX. For local calls within Illinois, you typically need to dial the full 10-digit number — even for calls within the same area code — because of mandatory 10-digit dialing imposed by the FCC for areas with overlay codes (most of Illinois's territory). For long-distance calls within the NANP, dial 1 + area code + 7-digit number.

Frequently asked questions about Illinois area codes

How many area codes does Illinois have?

Illinois currently has 13 active area codes: 217, 224, 309, 312, 331, 618, 630, 708, 773, 779, 815, 847, 872.

What is Illinois's original area code?

The oldest area code(s) in Illinois were assigned in 1947 as part of the original 86 NANP codes. These legacy codes typically covered the entire state at first, then were split as demand grew.

What time zone is Illinois in?

Illinois is in the Central time zone.

Will Illinois get more area codes?

As Illinois's population and number demand grow, NANPA may assign additional overlay codes. When the current codes run out of available prefixes, regulators announce public hearings and propose new codes. The AreaCodeCentral team tracks these announcements and updates the directory within 24 hours of any new code activation.