The term Great Plains, as used in the United States describes the westernmost portion of the vast North American Interior Plains which covers much of the interior of North America. The eastern portion of the interior plains, commonly called the Interior Lowlands, extend east all the way to the Appalachian Plateau.

The two areas of the North American Interior Plains are listed in this study as separate Geographical Regions know as: (4) Great Plains (this page); and (5) Interior Lowlands.

The Great Plains is a broad expanse of flat land (also called a plain), which has much of it covered in prairie, steppe, and grasslands. The Great Plains are located in the United States and Canada. It lies west of the Mississippi River tallgrass prairie in the United States and east of the Rocky Mountains in the U.S. and a small area of Canada.

The topography of the Great Plains consist of mostly high elevations grasslands rising in elevation as it becomes closer to the western mountains regions.

The continental Great Plains range from it′s northern extent within Canada in the southern portions of the provinces of Alberta and Saskatchewan then across into the US and found in the states of eastern Montana, western North Dakota, eastern Wyoming, western South Dakota, western Nebraska, eastern Colorado, western Kansas, extreme eastern New Mexico, western Oklahoma, and then into northwestern Texas which is the southernmost border.