Oak Brook, Illinois Area Code
Oak Brook, IL is officially utilizing an area code overlay in which area codes 331 and 630 serve the same geographic area. Ten digit dialing (area code + seven digit number) is necessary.
In addition to Oak Brook, IL area code information read more about area codes 331 and 630 details and Illinois area codes.
Oak Brook, IL is located in DuPage County and observes the Central Time Zone.
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