The area code 312 is located in Chicago, Illinois.
Area code 312 serves the vibrant city of Chicago, Illinois, covering the downtown area and parts of Cook County. Established in 1947, it is one of the original area codes in the United States. This area code includes major landmarks such as Millennium Park, the Art Institute of Chicago, and the iconic Willis Tower. Did you know that Chicago is home to the first skyscraper ever built? The Home Insurance Building, completed in 1885, set the stage for the city’s architectural innovation. Whether you’re exploring the Windy City’s rich culture or connecting with locals, area code 312 plays a key role in defining this bustling metropolitan hub.