Interior plains topography
in the US, the Interior plains are divided into the Central Lowland and the great Plains. The Northern boundary of the Central lowland is formed by the Canadian shield, the great Lakes, and the St. Lawrence River.
the Great plains are higher in elevation than the Central lowland, rising from about 600 meters to 1500 meters above sea level in the west.
In Canada's Prairie provinces, the Interior plains contain three different elevations, which are separated by escarpments. In general, the plains are gently rolling, gradually sloping down from west to east.