Where is the eastern time zone line in indiana?

In the late 1940s, the use of daylight saving time, known as fast time, became popular in cities. Indiana is officially in the central time zone, but some communities choose to follow fast time throughout the year, essentially aligning themselves with the Eastern time zone. The northwestern time zone boundary covers Lake, Porter, La Porte, Starke, Jasper and Newton Counties. These counties follow Central Time because of their proximity to the city of Chicago, IL.