What Borders the Great Plains?

The Great Plains—a vast grassland spanning central North America—is bounded by:

• West: Rocky Mountains
• East: Appalachian Mountains / Mississippi River (transition zone)
• South: Gulf of Mexico / Rio Grande
• North: Canadian Shield / boreal forest (approx. 49th–55th parallel)

It covers parts of 10 U.S. states and 3 Canadian provinces.