Conkle's Hollow State Nature Preserve is a gorge in Ohio within Hocking Hills State Park, known for its deep, cool, enclosed landscape. In some places the hollow narrows to about 100 feet across, and some regard it as the deepest gorge in the state. Cliffs rising roughly 200 feet above the valley floor create sheltered conditions below. That protected environment supports a notably rich plant community, including ferns, hemlock, and many kinds of wildflowers, making the preserve significant for both its dramatic geology and its distinctive habitat.