312 – Illinois Area Codes
|United States||Illinois||Code of City||Number|
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Fixed phone numbers in the United States, state Illinois (area code 312) are comprised of a single country code (+1), a 3 digit area code, a 3 digit local office code (or region code), and a 4 digit line code. Making a call with the wrong country, area, or region code can be costly. Browse our sites area and region codes by state and city to ensure you have the correct information for your calls. Each states page contains a list of the cities within that state and the numbers of that area. Also available are local times. So you don’t have to worry about calling too late or early again.
Getting calls from someone and want to know what state they are in? Try our reverse phone number lookup to find their location, it even works with mobile, toll free and other numbers. Just enter the number into the search field for instant results.