The Mackinaw State Forest is home to a rich diversity of animal species, including the Northern flying squirrel (Glaucomys sabrinus), American black bear (Ursus americanus), white-tailed deer (Odocoileus virginianus), wild turkey (Meleagris gallopavo), ruffed grouse (Bonasa umbellus), American marten (Martes americana), osprey (Pandion haliaetus), bald eagle (Haliaeetus leucocephalus) and pileated woodpecker (Dryocopus pileatus).

The Mackinaw State Forest is home to Michigan's two most critically endangered species: the Kirtland's warbler (Setophaga kirtlandii) and Hungerford's crawling water beetle (Brychius hungerfordi).

Indeed, of the five known locations in which Hungerford's crawling water beetles have been found, two are within the Mackinaw State Forest, one along the East Branch of the Black River and the other in Van Hetton Creek.

The Van Hetton Creek identifications are significant as they represented a new location beyond those originally identified when the Hungerford's crawling water beetle was categorized as endangered in 1994.

Graczyk planned to marry his fiancée on the evening of the day of the fatal accident,[3] and local legend asserts that the bridegroom's ghost haunts the overlook, especially at sunset.