At 1360 acres, this lake, the 3rd largest of the NE Illinois' NE Illinois' Chain O' Lakes system, is only 6' deep!
The Fox River empties into Grass Lake from the west as does Lake Marie on the east. The lake then empties into Fox Lake and Nippersink Lake on the south.
Abutting Chain O' Lakes State Park, Grass Lake is the southernmost lake of the "Northern Section" of the Chain.
Species of fish include Channel Catfish and Carp, which do well in shallow, murky waters.
Other lakes in the Chain are Lake Catherine, Channel Lake, Lake Marie, Pistakee Lake, and Redhead Lake.