317 Area Code – Indianapolis, Indiana: Location, Time Zone & History

Indianapolis has been served by area code 317 since it was among the original area codes assigned across North America in 1947, though its geographic footprint has shrunk twice as the region's population grew. In 1948 the northern two-thirds of Indiana -- including Gary, Hammond, East Chicago, South Bend, Elkhart and Fort Wayne -- was carved off into the new area code 219, leaving central Indiana as the remaining territory.

A second contraction followed in 1997, when area code 765 split off the counties surrounding the Indianapolis metro, narrowing coverage to the inner ring that now includes Carmel, Fishers, Noblesville and Greenwood alongside Indianapolis itself. As growth continued, boundary changes alone stopped being enough, and the overlay code 463 went into service on March 15, 2016, adding capacity without shrinking the map further; mandatory 10-digit dialing followed that October, after local alarm companies asked for extra time to adjust. The new code was reportedly chosen in part because 463 spells "IND" on a telephone keypad.

The population growth behind these numbering changes tracked Indianapolis's expanding profile in motorsports, pharmaceuticals, logistics, information technology, and insurance and finance. The Indianapolis Motor Speedway, home of the Indianapolis 500 since 1911, has helped give the region its identity as a racing hub, while employers such as Eli Lilly anchor its life-sciences sector.