John Bryan State Park — Public Lands Institute

Geological age: ~430–420 million years ago (bedrock); gorge carved ~12,000–14,000 years ago
Epoch: Silurian period (Llandovery–Wenlock); dolomite formed in shallow tropical sea; gorge incised during Late Pleistocene and early Holocene by glacial meltwater drainage
Taxa: 498 plants, 101 birds, 645 insects, 19 mammals, 14 reptiles, 11 amphibians
Native lands: Shawnee (Shawanwaki) · Miami · Adena and Hopewell cultures (500 BCE–500 CE); Little Miami River corridor a major Shawnee territory; Shawnee ceded Ohio lands via Treaty of Greene Ville 1795
Ecology: Gorge microclimate supporting relict northern plant communities; Canadian yew, white cedar, walking fern — species absent from surrounding landscape; National Natural Landmark
Hydrology: Little Miami River (Ohio State Scenic River; National Wild & Scenic River); Yellow Spring iron-rich seep; Jacoby Creek tributary
Acreage: 752 acres (park); 268 acres (Clifton Gorge SNP)
Conservation: Ohio State Park; National Wild and Scenic River (Little Miami River); Ohio State Scenic River (Little Miami River)
Endangered species: none documented
GPS: 39.7960° N, 83.8310° W