Millgrove Township is one of twelve townships in Steuben County, Indiana, United States. As of the 2020 census, its population was 1,619, up from 1,577 at 2010, and it contained 960 housing units.
Fawn River State Fish Hatchery was listed on the National Register of Historic Places in 1997.
According to the 2010 census, the township has a total area of , of which (or 92.80%) is land and (or 7.20%) is water. Lakes in this township include Bell Lake, Brown Lake, Chair Factory Lake, Lake Gage, Lake Syl-van, Lime Lake, Lime Lake, Perch Lake, Rhodes Lake, Sally Owen Lake, Tamarack Lake and Warner Lake. The stream of Crooked Creek runs through this township.
(This list is based on USGS data and may include former settlements.)
The township contains three cemeteries: Carlton, Greenlawn and Mill Grove.