What is area code 539?

Area code 539 is an overlay area code for the state of Oklahoma in the United States, which serves the same geographic area as area code 918. It was established on April 1, 2011 as a way to provide additional phone number options for residents and businesses in the region. Calls within the 539 area code can be made by dialing either the 10-digit phone number (area code + local number) or the traditional 7-digit phone number.