In 1961, the Indiana legislature repealed the 1957 law that made Central Time the official time of Indiana, allowing any community to observe Daylight Saving Time. The Interstate Commerce Commission divided Indiana into the Central Time Zone and the Eastern Time Zone. However, neither the time zone line nor Daylight Saving Time was observed uniformly.
The United States Congress subsequently passed the Uniform Time Act of 1966, which required all states to observe Daylight Saving Time. Prior to this law, each state was allowed to decide this issue for itself. Governor Roger D. Branigin asked the USDOT to put all of Indiana back in the Central Time Zone a year later. Over the next two years, the USDOT held several hearings in response to Governor Branigan's request.
The USDOT chose to divide Indiana between the Central Time Zone and the Eastern Time Zone. Six counties near Chicago (Lake, Porter, LaPorte, Jasper, Newton, and Starke) and six counties near Evansville (Posey, Vanderburgh, Warrick, Spencer, Gibson, and Pike) were placed in the Central Time Zone respecting Daylight Saving Time. The rest of the state was placed in the Eastern Time Zone; the state received a special waiver to exempt parts of itself from Daylight Saving Time.
Most parts of the state that were in the Eastern Time Zone did not observe Daylight Saving Time. However, Floyd, Clark, and Harrison counties; and Ohio and Dearborn counties unofficially observed Daylight Saving Time due to their proximity to major cities that observed it. A federal lawsuit was filed in 1968 to force USDOT to enforce Daylight Saving Time in Indiana; they won. As a result, USDOT was ordered to provide a plan for its enforcement.
In 1972, the Indiana General Assembly overturned a veto by Governor Whitcomb to place Indiana's northwest and southwest corners in the Central Time Zone during Daylight Saving Time and place the rest of the state in Eastern Standard Time subject to federal approval. Several counties in eastern Indiana chose to observe Daylight Saving Time unofficially despite Indiana statute.
Attitudes began to change in the 1990s when Indiana's complicated time zone situation was considered to prevent economic growth. Starke County asked USDOT to move it from the Central Time Zone to the Eastern Time Zone for the third time; this time it was granted starting October 27th 1991. Pulaski County returned to Eastern Time on March 11th when Daylight Saving resumed. When Standard Time resumed on November 3rd all five Southwest Counties (Daviess, Dubois, Knox, Martin and Pike) returned to Eastern Standard Time.
Some argue that the entire state should move to Central Time while others would prefer that it revert back to non-observance of Daylight Saving Time. Opponents of putting all of Indiana in one time zone often cite out-of-state cities as their reason for opposition while supporters of a common time zone often claim that it would preserve interstate business with other regions.
