The Lewis Overthrust is a geologic thrust fault structure of the Rocky Mountains within Glacier National Park in Montana, USA and Waterton Lakes National Park in Alberta, Canada, as well as into Lewis and Clark National Forest. It provides scientific insight into geologic processes happening in other parts of the world, like the Andes and the Himalaya Mountains. Scientific study of this region is practical because the original rock characteristics were well-preserved and recently sculpted by glaciers. The Lewis and Livingston mountain ranges are the visible reminders of this fault. The Rocky Mountain Front is the easternmost portion of the Lewis Range which rises abruptly 4,000 to 5,000 feet (1,200 to 1,500 m) above the Great Plains.