Great Plains

Great Plains, large plateau in the western region of central North America, extending for over 1,500 mi (2,400 km) from the Saskatchewan River in northwest Canada to the Rio Grande in Mexico and the Gulf coastal plain in the southern part of the United States. The plateau slopes gently downward from the Rockies in the west, extending about 400 mi (640 km) east. The natural vegetation is buffalo grass, and the area generally has hot summers and cold winters with an average annual rainfall of 20 in (50 cm). The plains are the “granary of the world” owing to their vast wheat production; livestock is also important.