Fall line (topography)

The fall line is a line on a map where the land changes from rolling hills to more flat land. It's kind of like a line between two different types of land. The higher, hilly land is usually called the "upland" and the lower, flat land is called the "lowland". The fall line is usually found near rivers and streams, because that's often where the land changes from hilly to flat. You can think of the fall line as a kind of border between the different types of land.