Facts About the Great Plains

By Meg Michelle
The Badlands of South Dakota are some of the most recognizable formations of the Great Plains.
PetrBednarik/iStock/Getty Images

The Great Plains stretch from Canada down to Mexico, cutting through the central part of the United States, bounded by the Rocky Mountains to the west and the Missouri River to the east. Once an ancient ocean seabed, the large stretch of land is home to some astounding geological formations as well as wildlife unique to the area.

Great Plains Formation

The Great Plains are exceptionally flat because they used to be the bed of what was once the interior sea. The Great Plains were completely submerged, 570 million years ago. As the tectonic plates began to shift and the North American continent thrust upward, the sea flowed away, exposing the Plains. Rivers, glaciers, wind and continued continental uplift shaped the Plains over the course of hundreds of millions of years, although most of the modern formations were created within the last two million years. Geologically speaking, the Great Plains are a relatively young environment.

Notable Geological Formations

Because the Great Plains are so vast, they have a variety of stunning geological formations. For instance, in central Texas there is a sudden upthrust of land in the middle of otherwise level plains. However, the uplift itself is so extremely flat that early settlers named it the Llano Estacado (Staked Plain) because they had to mark their land by stakes; there were no natural landmarks by which to separate settlements. Farther north are the Badlands of South Dakota. The Badlands are a series of flat-topped rocks in which gullying has taken place, creating uneven valleys. The formation was created because the land is made of clay-rich material, such as shale, which water cannot penetrate. Rain runoff over the eons chipped away at the surface of the rock, creating the valleys. The Great Plains are also home to the High Plains, or Ogallala, Aquifer, which spans from Canada all the way to Texas. As one of the largest sources of fresh water in the world, it's thought to hold one quadrillion gallons of water.

Vegetation of the Great Plains

The Great Plains are primarily grasslands. In particular, they are mostly covered with short grasses, such as blue grama and buffalograss. These short grasses abound because the land has so long been used as grazing pasture for livestock, which favor such grass as feed. Although the Plains are now almost totally covered by grasslands, they were not always so. Prior to the last ice age, ten millennia ago, there were many trees and perhaps even forests across the landscape. However, as the ice retreated, the climate that remained was semi-arid, leaving the land predisposed to grasses.

Animals of the Great Plains

In the Great Plains, bison are the largest and most recognizable animals. Although once 60 million strong, their numbers have now dwindled to 20,000, making them among the most threatened species on the Plains. Other animals include black-footed ferrets and pronghorn antelope, as well as many species of grassland birds, such as grouse, hawks and vultures. The Plains are also home to many species of bat, foxes, and deer.

About the Author

An avid lover of science and health, Meg Michelle began writing professionally about science and fitness in 2007. She holds a bachelor’s degree in physics from Creighton University and master’s degree in science writing from Johns Hopkins. Her work has appeared in publications such as EARTH Magazine.