(Ohio)
Conkle's Hollow State Nature Preserve is a deep, cool gorge, which is only 100 feet wide in places and is considered by some to be the deepest in Ohio. The cliffs above the gorge are about 200 feet tall. The valley floor is covered in many species of plants, such as ferns, hemlock, and various wildflowers. It is located within Hocking Hills State Park. (Ref: https://en.wikipedia.org/wiki/Conkle's_Hollow_State_Nature_Preserve)