Jefferson Township is one of thirteen townships in Grant County, Indiana, United States. As of the 2010 census, its population was 5,839 and it contained 1,758 housing units.
The Cumberland Covered Bridge was listed on the National Register of Historic Places in 1978.
According to the 2010 census, the township has a total area of , of which (or 99.67%) is land and (or 0.33%) is water. Lakes in this township include Dollar Lake. The streams of Branch Creek, Cane Run, Crawford Creek, Lake Branch, Mat Run, Round Run and Upland Drain run through this township.
The township contains two cemeteries, Shiloh and Jefferson.
Jefferson Township residents may obtain a free library card from the Barton Rees Pogue Memorial Public Library in Upland.