Indiana currently utilizes 8 area codes. When first established by AT&T and the Bell System in 1947, 317 covered the northern two-thirds of Indiana including Indianapolis and 812 covered southern Indiana. The most recently added was 463 in 2016 as an overlay to 317. Today, 317 is the most populated with an estimated 1.5 million of the state's 6.5 million residents.
Sources: North American Numbering Plan Administration (NANPA), telecom providers, and the U.S. Census Bureau.