Appalachian Ohio is a bioregion and political unit in the southeastern part of the U.S. state of Ohio, characterized by the western foothills of the Appalachian Mountains and Appalachian Plateau. The Appalachian Regional Commission defines the region as consisting of thirty-two counties. This region roughly overlaps with the Appalachian mixed-mesophytic forests, which begin in southeast Ohio and southwest Pennsylvania and continue to north Georgia and Alabama. The mixed-mesophytic forest is found only in Central and Southern Appalachia and eastern/central China. It is one of the most biodiverse temperate forests in the world.Geologically, Appalachian Ohio corresponds closely to the terminal moraine of an ancient glacier that runs southwest to northeast through the state. Areas south and east of the moraine are characterized by rough, irregular hills and hollows, characteristic of the Allegheny Plateau and Cumberland Plateaus of the western Appalachian Plateau System. Unlike eastern Appalachia, this region does not have long fin-like ridges like those of the Ridge-and-Valley Appalachians subranges, but a network of rocky hollows and hills going in all directions.
