Mission Township is located in LaSalle County, Illinois.

As of the 2010 census, its population was 3,972 and it contained 1,083 housing units.

One of these ministers, Jessie Walker, actually has a memorial at the United Methodist Church in Sheridan, which is the seat of the township.

The township border is defined by where the Fox River goes southwest, turns south, then continues to go east, south, west, northwest, north, and then it then curves to go southwest again, forming an awkward "S" shape on the map.

The community of Sheridan resides at the beginning of the bends in the river, and the community of Norway resides where the river flows north, and then curves around to flow southwest.