Geologic History. The Highlands Nature Sanctuary is a unique geological crossroads where six major landforms meet: glaciated and unglaciated terrain, sandstone and shale, dolomite and limestone, and the western plateau blending into Appalachian hill country. This rare convergence fosters exceptional biodiversity and underscores the area’s significance. Highland County transitions from flat, glaciated farmland to rolling hills with rich soils that support dense beech-maple forests and vibrant wildflowers, a rare Ohio landscape. The Highlands also mark where limestone and dolomite bedrock from the west meet sandstone and shale from the east. Exposed glaciated limestone, shared only with Clifton Gorge near Yellow Springs, creates stunning limestone canyons, cliffs, and diverse plant habitats. Rocky Fork Gorge showcases 400-million-year-old dolomite cliffs, weathered into intricate formations that act as natural hanging gardens. The region is also home to one of Ohio's densest cave systems, with 23 caves providing critical habitats for bats, rare isopods, and other specialized species. The Highlands’ geological wonders include massive slump blocks, like Steamboat Rock and the Three Sisters, and iconic formations like a rock face resembling a woman’s profile, softened by ferns. These features add to the region's natural beauty and continue to inspire visitors and explorers.

Cave Country. Cave Road located within the Highlands Nature Sanctuary is one of Ohio's premier limestone cave regions, with 23 caves, including eight of notable size. These caves, suspended high above Rocky Fork Gorge, are remnants of ancient underground streams shaped by glacial runoff and erosion. Seven of the largest caves were originally part of Seven Caves Park. These caves have been restored to their natural state, with trails and lights removed. Two of the caves remain open seasonally from July 1st until November 15. These caves are critical habitats for bats, cave-adapted invertebrates, and rare species like the Frost Cave isopod. Preserving the caves and surrounding lands safeguards these ecosystems and Ohio’s rich geological history.