Kinnikinnick Fen is a 154-acre wetland complex situated along Kinnikinnick Creek in Green Township. A "fen" is a type of wetland (along with bogs, swamps, and marshes) that is fed by spring water that is mineral-rich and alkaline, rather than containing the acidic water that you find in most of the other wetland types. As a result of the unusual alkaline water chemistry, several threatened plant species are found here, along with a couple of Ohio Threatened animals...Kirtland's snake and the Spotted turtle.

The park features a 1.5 total mile walking path that follows Kinnikinnick Creek and passes through wetlands and sedge meadows, woods, and fields of wildflowers and native grasses formerly in agriculture. Three observation decks offer wonderful views of Kinnikinnick Creek and oxbow wetlands.