[3] The eastern two-thirds of Wilson Lake lies in the northern part of the township.

Another of the river's tributaries, Blood Creek, flows northeast through the extreme southeastern corner of the township.

[1] Plymouth Township lies within Unified School District (USD) 112, based in Lorraine.

K-232, a north–south route, enters the northeastern part of the township from the north and runs south along the eastern shore of Wilson Lake before turning slightly southeastward and exiting the county.

A network of mostly unpaved county roads is laid out in a rough grid pattern across the township.

Another paved road, 200th Boulevard, enters the township from the west 3.5 miles south of Dorrance, turns north, and runs north through Dorrance before finally terminating at the southern shore of Wilson Lake.