Some of the major features of Ohio's landscape include the plains regions, the Allegheny or Appalachian Plateau, a bluegrass area and the Lake Erie shore area to the north. Despite its relatively small size of under 45,000 square miles, Ohio has a variety of natural landforms.
Glacial activity during the last Ice Age played a large role in the development of the Ohio landscape as it exists today. Large parts of the state were covered with ice with the southern edge of the glacial advance being near the shores of the Ohio River, while some areas were not, accounting for the variation in landforms.
The Great Lakes Plains stretch roughly in a band along the shores of Lake Erie eastward, while the Tills Plains encompass the southwestern and central-west parts of the State. the Allegheny Plateau includes all of eastern Ohio until it runs into the Great Lakes Plains to the north. The bluegrass areas of Kentucky extend into the south-central portion of Ohio.
Natural rock arches are one of the more unusual landforms found in several areas of Ohio. Larger rock bridges includes a 20-foot-wide arch called Rockbridge that spans a 100-foot ravine and another called Rockhouse that arches nearly 40 feet high across a 200-foot stretch in Hills State Park.