Idaho is part of the world’s longest mountain chain above sea level, extending from the tip of South America to Alaska’s north coast. Its widest section lies in the western United States, from the Sierra Nevada to the Rocky Mountains. The Lost River Range is one of many smaller mountain ranges between the Rockies and the Sierra Nevadas. The earth’s crust between the Sierra Nevada and Rocky Mountains, including the Great Basin, is stretching about 1/2 inch per year and getting thinner. Every so often, over spans of a few hundred to a few thousand years, the crust breaks along old fracture lines known as faults. The valleys drop and the mountains rise, creating the Basin and Range landscape visible here.