Butler is a city in DeKalb County, Indiana, United States. The population was 2,684 at the 2010 census. Butler was platted in 1856 when the r…Butler is a city in DeKalb County, Indiana, United States. The population was 2,684 at the 2010 census. Butler was platted in 1856 when the railroad was extended to that point. It was likely named for David Butler, a pioneer. Butler was incorporated as a town in 1866, and as a city in 1903.