Physiographic regions are a means of defining Earth's landforms into independently distinct, mutually exclusive areas, independent of political boundaries. It is based upon the classic three-tiered approach by Nevin M. Fenneman in 1916, that separates landforms into physiographic divisions, physiographic provinces, and physiographic sections.[1]
The classification mechanism has become a popular geographical tool in the United States, indicated by the publication of a USGS shapefile that maps the regions of the original work and the National Park Services's use of the terminology to describe the regions in which its parks are located.[2]
Originally used in North America,[1] the model became the basis for similar classifications of other continents.[3]