Rocky Mountains or Rockies, great chain of rugged mountain ranges in western North America, extending from central New Mexico to northeastern British Columbia, a distance of about 3220 km (about 2000 mi). The Rockies are bordered on the east by the Great Plains and on the west by the Great Basin ...

Rocky Mountains or Rockies, great chain of rugged mountain ranges in western North America, extending from central New Mexico to northeastern British Columbia, a distance of about 3220 km (about 2000 mi). The Great Basin and the Rocky Mountain Trench, a valley running from northwestern Montana to...