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area code

Biggest city:





Central (GMT -6)

Nearby area codes: 

Zip codes



Major Cities:

Rockford, Joliet, DeKalb


Average Income:





Unemployment Rate:

Area code 779 is a telephone area code serving the state of Illinois in the United States. Here are some key details about this area code: Implementation and Origin: The 779 area code was assigned on February 6, 2004, and went into service on March 17, 2007. It was created from the 815 area code previously by means of an area code split or overlay. This development was necessary due to the growing demand for phone numbers in the state of Illinois​​​​. Cities and Counties Covered: The area code covers 122 cities and 23 counties in Illinois, including major areas like Joliet, Rockford, Plainfield, DeKalb, and Crystal Lake. Counties within its coverage include Winnebago County, Will County, Dekalb County, McHenry County, and Livingston County. This wide coverage makes area code 779 a vital component of Illinois's telecommunications infrastructure​​. Time Zone and Dialing Pattern: Area code 779 is located in the Central Standard Time (CST) zone. It observes Daylight Saving Time, meaning that the clocks are adjusted forward by one hour during the warmer months of the year to extend evening daylight, and then back again in the autumn. The dialing pattern for local calls within the same NPA (Numbering Plan Area) in the 779 area code is 1+10 digits​​. In summary, area code 779 is essential for telecommunications in Illinois, particularly due to its overlay with area code 815. Its implementation reflects the growing need for additional phone numbers in the region, and its coverage of several key cities and counties underscores its importance in Illinois's communication network. The area code's placement in the Central Time Zone and adherence to Daylight Saving Time are also significant operational aspects.
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