The Interior Plains are bordered on the west by the Rocky Mountains.

The Rocky Mountains, a major mountain range in North America, extend from Canada through the United States and into New Mexico. This range is characterized by its rugged terrain, high peaks, and diverse ecosystems, contrasting sharply with the flat and rolling landscapes of the Interior Plains. The Rockies play a significant role in shaping the climate and hydrology of the region, serving as a natural barrier that influences weather patterns and water drainage systems.