Time in Indiana

The location of the U.S. state of Indiana at the boundary of the Eastern and Central time zones has led to the state being split between the two time zones. The official dividing line has moved progressively west from its original location on the Indiana–Ohio border, to a position dividing Indiana down the middle, and finally to its current location along much of the Indiana–Illinois border. Being on the western frontier of the Eastern time zone resulted in opposition from many in the state to observing daylight saving time for decades. The 2005 decision by the Indiana General Assembly to implement daylight saving time remains controversial.

Indiana observes Eastern Time, except for twelve of its ninety-two counties, which observe Central Time. Six of these counties are in northwestern Indiana, near Chicago (which observes Central Time), and six are in southwestern Indiana, near Evansville, where the metro area includes portions of southeastern Illinois and western Kentucky, which also observe Central Time. The twelve counties are:

Since April 2, 2006, all counties in Indiana observe daylight saving time.

The most extensive study of time zone history in Indiana has been published in The American Atlas (1978) by Thomas G. Shanks, where the author identifies 345 areas in the state with a different time zone history for each.

The tz database lists 11 time zones for Indiana, where each zone is defined as a geographic area that observed the same offsets from UTC since January 1, 1970 (the UNIX epoch). The diagrams in this article are colored to show these 11 zones and a key is provided below.

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