Illinois Area Code

IIllinois, a state in the Midwestern United States, is renowned for its diverse geography, including bustling urban centers like Chicago, picturesque rural landscapes, and the tranquil beauty of the Mississippi River. As the nation's transportation hub, it has played a pivotal role in commerce and culture. Illinois is known for its vibrant cities, world-class museums, and contributions to various industries, from agriculture to technology. It's also home to the iconic Route 66, a historic highway that symbolizes the American road trip experience.

State Illinois
State Abbreviation: IL
State Nickname: Prairie State Equality State
Capital City Springfield
Area Codes 217, 224, 309, 312, 331, 618, 630, 708, 773, 779, 815, 847, 872
Timezone Eastern Time (ET),Central Time Zone (CT)
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What time zone is Illinois?

Illinois primarily follows the Central Time Zone (CT), which is UTC-6 during Standard Time (winter) and UTC-5 during Daylight Saving Time (summer). However, some eastern areas along the border with Indiana and Kentucky adhere to the Eastern Time Zone (ET), shifting from UTC-5 to UTC-4 during Daylight Saving Time. The specific time zone within Illinois can vary depending on location, but the majority of the state observes Central Time.

Note that the start and end dates of daylight saving time can change


Illinois' area code history reflects its population growth and changing telecommunications needs. Initially served by a single area code, 312, the state has introduced new codes like 708, 815, and 630 to accommodate growth. Splits and overlays have further divided the state, resulting in numerous area codes, such as 773, 847, 630, and 331, reflecting Illinois' dynamic demographics and evolving telecommunications infrastructure.


All Area Codes in Illinois

This table provides a quick overview of all area codes, their locations, and some historical context for each.

Area Code Location History and Details
312 Downtown Chicago Covers downtown Chicago and its immediate neighborhoods.
773 Chicago (North and West) Encompasses a large portion of Chicago, extending to the north and west.
872 Chicago Overlay An overlay code for 312 and 773, serving the same areas.
708 South Suburbs of Chicago Includes suburbs west and south of Chicago.
630 Western Suburbs of Chicago Covers the western suburbs of Chicago, including areas like Naperville and Wheaton.
331 Western Suburbs Overlay An overlay code for 630, serving the same regions.
815 Northern Illinois Serves northern Illinois, including cities like Rockford and Joliet.
847 Northern Suburbs of Chicago Encompasses the northern suburbs of Chicago, including areas like Evanston and Arlington Heights.
224 Northern Suburbs Overlay An overlay code for 847, serving the same areas.
779 Northern Illinois Overlay Another overlay code for 815, serving northern Illinois.
618 Southern Illinois Covers southern Illinois, including cities like Belleville and Carbondale.
309 Western and Central Illinois Serves western and central Illinois, including Peoria and Bloomington.
217 Central Illinois Covers central Illinois, including Springfield, the state capital.

Largest Cities in Illinois with area codes

Quick overview of large cities, their area codes, and some historical context for each in Illinois.

Name Area Code History and Details
Chicago 312, 773, 872 Chicago is the largest city in Illinois and one of the largest in the United States. It's known for its diverse culture, iconic skyline, and economic significance.
Aurora 630 Aurora is the second-largest city in Illinois, located in the western suburbs of Chicago. It has a growing population and diverse community.
Rockford 815 Rockford is the third-largest city in Illinois and is located in the northern part of the state. It's known for its manufacturing heritage.
Joliet 815 Joliet is a city in northern Illinois with a rich history and is often referred to as the "City of Steel" due to its industrial past.
Naperville 630 Naperville is a prosperous city in the western suburbs of Chicago known for its excellent schools and quality of life.
Springfield 217 Springfield is the capital city of Illinois, located in central Illinois. It has historical importance, including the Abraham Lincoln Presidential Library and Museum.
Peoria 309 Peoria is in central Illinois and is a hub for healthcare and manufacturing industries.
Elgin 847 Elgin is in the northern suburbs of Chicago and is known for its cultural diversity and historic architecture.
Waukegan 847 Waukegan is located along the shores of Lake Michigan in northern Illinois and has a rich industrial history.
Champaign 217 Champaign is in central Illinois and is home to the University of Illinois at Urbana-Champaign, contributing to a vibrant educational and research community.