The Rocky Mountains stretch some 3,000 miles from British Columbia and Alberta in Canada through Idaho, Montana, Wyoming, Colorado and down to New Mexico in the U.S. The range offers dramatic wilderness, diverse wildlife and alpine lakes. Colorado’s Rocky Mountain National Park is traversed by 300 miles of hiking trails and famously scenic Trail Ridge Road.
Area: 382,894 mi²
The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. Wikipedia
Area: 58,484 mi²
The Appalachian Mountains, often called the Appalachians, are a system of mountains in eastern North America. Wikipedia
Area: 737,000 sq miles