The Cumberland Plateau is the southern part of the Appalachian Plateau. It includes much of eastern Kentucky and western West Virginia, part of Tennessee, and a small portion of northern Alabama. The terms "Allegheny Plateau" and the "Cumberland Plateau" both refer to the dissected plateau lands lying west of the main Appalachian Mountains. The terms stem from historical usage rather than geological difference, so there is no strict dividing line between the two. Generally speaking, the Allegheny Plateau is dominated on the Allegheny River system, while the Cumberland Plateau is dominated by the Cumberland River and Tennessee River systems.


It is a deeply dissected plateau, with topographic relief commonly of about four hundred feet (120 meters), and frequent sandstone outcroppings and bluffs. Many coal seams are present in the area, and the Cumberland Plateau has for many years been heavily mined. At the Pottsville Escarpment, which is the transition from the Cumberland Plateau to the Bluegrass in the north and the Pennyrile in the south, there are many spectacular cliffs, gorges, rockhouses, natural bridges, and waterfalls. In Tennessee it borders the Highland Rim east of the Nashville Basin. In Kentucky, the appearance and height of the resulting hills increases dramatically from northwest to southeast, with the hills in the westernmost areas of the plateau having a relief of around 200 feet and an appearance very similar to the knobs region, whereas areas near Black Mountain
have a spectatular relief that can exceed 2500 feet.

It is contiguous with the Allegheny Plateau on the northern side, the only real difference being local naming. The sedimentary rocks that compose both plateaus are of Mississippian and Pennsylvanian geological age, composed of near shore sediments washed westward from the original Appalachian Mountains. Some rock layers were laid down in shallow coastal waters, some, including bituminous coal seams were laid onshore in swampy environments. These are interlaced with delta formations of cross-bedded sandstones and occasionally conglomerate. There are numerous discontinuities in the beds, where they were raised high enough to be eroded, then lowered to have more sediments added on top.

The plateau contains some of the largest stretches of contiguous forest in the eastern United States; however, the rich, native deciduous forests are increasingly being converted to monoculture pine plantations. Ecologically, it is a part of the Appalachian mixed mesophytic forests ecoregion.