Physiographic region is a system of territorial division of the earth's surface, based on the identification and study of a system of subordinate natural regions that have internal unity and unique individual features of nature.
There may be following 7 physiographic regions:
- Appalachian (two divisions of the range, the Blue Ridge and the Valley and Ridge, are composed of narrow, rocky formations that distinguish the mountains from surrounding valleys)
- Atlantic Plain (there are no mountains in this region of North America. It is composed primarily of sedimentary rock and unlithified sediments and is primarily used for agriculture. )
- Canadian Shield (containing a variety of small lakes, thin layers of soil and rolling hills. Lakes are \the result of glacial erosion during the last ice age)
- Interior Plains (with shallow inland seas. Sediments from the shield and the Rocky Mountains were deposited in these seas over millions of years)
- Pacific Coast Ranges (with Pacific Ocean, as a natural western border, and the coastal mountain ranges forming the eastern border)
- Baja California Peninsula (with four desert areas, although it is surrounded by waters from three sides)
- Andean Mountain System (Longest mountain range in the world and the highest outside of Asia with volcanoes)
Encyclopedia Britannica, The Canadian Encyclopedia, USA Today, Wikipedia.