The area comprising Harrison Lake State Park was at one time part of a vast wetland. This mysterious area contained towering trees and soggy black soil, and was a haven for the swamp rattlesnake (or massassauga, as it is also known). Very little remains of that once great swamp, but the park still harbors unique natural features associated with wetlands. Great blue herons and common egrets can be sighted at the lake's shallow western end. Numerous songbirds inhabit the park's meadows and woodlands, such as the vesper sparrow, common yellowthroat and brown thrasher. Several species of reptiles and amphibians find the park's habitat suitable. Box turtles, painted turtles, garter snakes, green frogs and American toads are found here. Small mammals such as red fox, raccoon, skunk and the uncommon thirteen-lined ground squirrel are frequently seen.

• Take a hike: A 3.5-mile hiking trail circles the lake and provides the opportunity to explore the scenic lakeshore and woodlands.