Rocky Mountains

The Rocky Mountains, also known as the Rockies, are a major mountain range in western North America. The Rocky Mountains stretch more than 3,000 miles from the northernmost part of British Columbia, in western Canada, to New Mexico, in the Southwestern United States. Located within the North American Cordillera, the Rockies are somewhat distinct from the Pacific Coast Ranges, Cascade Range, and the Sierra Nevada, which all lie farther to the west.

The Rocky Mountains formed 80 million to 55 million years ago during the Laramide orogeny, in which a number of plates began sliding underneath the North American plate. The angle of subduction was shallow, resulting in a broad belt of mountains running down western North America.