Rocky Mountain Trench

The Rocky Mountain Trench is a long valley on the western side of the Rocky Mountains in North America, sometimes called the Valley of a Thousand Peaks, running about 1,600 kilometers from Flathead Lake in Montana to the Liard River near the British Columbia-Yukon border. It separates the Rocky Mountains to the east from the Columbia and Cassiar Mountains to the west, with a floor 3 to 16 kilometers wide sitting 600 to 900 meters above sea level. The trench is primarily a product of geologic faulting rather than glacial carving alone: its northern section follows the Tintina strike-slip fault while its southern portion formed through normal faulting during the Cenozoic, the two aligning along a pre-existing basement ramp with more than 10 kilometers of vertical offset.