Johnson Township is one of eleven townships in LaGrange County, Indiana. As of the 2020 census, its population was 3,546 (up from 3,392 at 2010) and it contained 2,076 housing units.
Johnson Township was founded in 1837.
According to the 2010 census, the township has a total area of , of which (or 93.38%) is land and (or 6.62%) is water.