Rifle River State Recreation Area is a Michigan state park on the upper Rifle River within the Au Sable State Forest, encompassing 4,449 acres of lakes, streams, and forest. Once the private Grousehaven retreat of Harry Mulford Jewett, it was purchased by the Michigan Department of Conservation in 1945, first served as a fish and game research field laboratory, and became a state recreation area after the Parks Division acquired it in 1963. Its quiet waterways, where boat motors are barred, support paddling and fishing, while campgrounds, cabins, beaches, and trails make it a year-round destination shaped by both recreation and long-running conservation research.