The Unglaciated Allegheny Plateau is located in an arc around southeastern Ohio into western Pennsylvania and West Virginia. This area is a dissected plateau, characterized by sandstone, shale, and many coal seams. This is the part of the Allegheny Plateau that lies outside the continental glaciation of the ice ages.

One of the most spectacular and scenic areas in this region is located in southeast Ohio, and is known as the Hocking Hills region. This area, similar to but smaller than the Red River Gorge in the Cumberland Plateau in Kentucky, features cliffs, rock shelters and waterfalls.

The Ohio River roughly bisects the Unglaciated Allegheny Plateau in roughly a north-northeast to south-southwest direction. Other significant rivers in the plateau include the Muskingum River in Ohio, the Youghiogheny River and Allegheny River in Pennsylvania, and the Kanawha River in West Virginia. The Kanawha River (pronounced "ken - AAH", that is, with an extended flat A) is formed by the confluence of the New River and the Gauley River . All three rivers are known for their spectacular deep gorges.

The largest city in the Unglaciated Allegheny Plateau is Pittsburgh, Pennsylvania.