The mountain range that runs through the western United States is the Rocky Mountains, often simply referred to as the Rockies. This vast range extends over 3,000 miles from Canada down to New Mexico, characterized by its high peaks, diverse ecosystems, and stunning landscapes. The Rockies provide numerous outdoor recreational opportunities, including hiking, skiing, and rock climbing. National parks like Yellowstone and Rocky Mountain National Park showcase the natural beauty and wildlife of this geologically fascinating region.