Appalachian Plateau in the context of "Interior Plain"

The Appalachian Mountains, often called the Appalachians, are a mountain range in eastern to northeastern North America. The term "Appalachian" refers to several different regions and mountain systems associated with the mountain range, and its surrounding terrain. The general definition used is one followed by the United States Geological Survey and the Geological Survey of Canada to describe the respective countries' physiographic regions. The U.S. uses the term Appalachian Highlands and Canada uses the term Appalachian Uplands; the Appalachian Mountains are not synonymous with the Appalachian Plateau, which is one of the seven provinces of the Appalachian Highlands.

The Appalachian range runs from the Island of Newfoundland in Canada, 2,050 mi (3,300 km) southwestward to Central Alabama in the United States; south of Newfoundland, it crosses the 96-square-mile (248.6 km) archipelago of Saint Pierre and Miquelon, an overseas collectivity of France, meaning it is technically in three countries. The highest peak of the mountain range is Mount Mitchell in North Carolina at 6,684 feet (2,037 m), which is also the highest point in the United States east of the Mississippi River.

The Catskill Mountains, also known as the Catskills, are a physiographic province and subrange of the larger Appalachian Mountains, located in southeastern New York. As a cultural and geographic region, the Catskills are generally defined as those areas close to or within the borders of the Catskill Park, a 700,000-acre (2,800 km) forest preserve protected from many forms of development under New York state law.

Geologically, the Catskills are a mature dissected plateau, a flat region subsequently uplifted and eroded into sharp relief by watercourses. The Catskills form the northeastern end of the Allegheny Plateau (also known as the Appalachian Plateau).

The Great Plains is a broad expanse of flatland in North America. The region stretches east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. They are the western part of the Interior Plains, which include the mixed grass prairie, the Tallgrass prairie between the Great Lakes and Appalachian Plateau, and the Taiga Plains and Boreal Plains ecozones in Northern Canada. "Great Plains", or Western Plains, is also the ecoregion of the Great Plains or the western portion of the Great Plains, some of which in the farthest west is known as the High Plains.

The Great Plains lie across both the Central United States and Western Canada, encompassing:

The Interior Plains is a vast international region that spreads across the Laurentian craton of central North America. It extends along the east flank of the Rocky Mountains from the Gulf Coast region to the Arctic Beaufort Sea. In Canada, it encompasses the Canadian Prairies separating the Canadian Rockies from the Canadian Shield, as well as the Boreal Plains and Taiga Plains east of the Mackenzie and Richardson Mountains. In the United States, it includes the Great Plains of the West/Midwest and the tallgrass prairie region to the south of the Great Lakes extending east to the Appalachian Plateau region.

The Cumberland Plateau is the southern part of the Appalachian Plateau in the Appalachian Mountains of the United States. It includes much of eastern Kentucky and Tennessee, and portions of northern Alabama and northwest Georgia. 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. Two major rivers share the names of the plateaus, with the Allegheny River rising in the Allegheny Plateau and the Cumberland River rising in the Cumberland Plateau in Harlan County, Kentucky.

The Allegheny Front is the major southeast- or east-facing escarpment in the Allegheny Mountains in southern Pennsylvania, western Maryland, eastern West Virginia, and western Virginia. The Allegheny Front forms the boundary between the Ridge-and-Valley Appalachians to its east and the Appalachian Plateau (locally called the Allegheny Plateau) to its west. The Front is closely associated with the Appalachian Mountains' Eastern Continental Divide, which in this area divides the waters of the Ohio/Mississippi river system, flowing to the Gulf of Mexico, from rivers flowing into Chesapeake Bay and from there into the Atlantic Ocean.

The Allegheny Front and the Eastern Continental Divide do not always coincide; for example, the North Branch of the Potomac River begins well west of the Front, at the Fairfax Stone near the southwestern tip of Maryland, about 10 miles (16 km) and across the actual divide from the headwaters of the Youghiogheny River draining northwards into the Monongahela and Ohio rivers. The Front and the Divide diverge completely in central Pennsylvania where the West Branch Susquehanna River originates north of the Allegheny Front.