The Teton Range:
Young, Restless, and Still Rising: In geologic time, these mountains are the energetic teenagers of the Rocky Mountain chain: active, growing, yet sculpted by erosion.
The Rise of the Range:
Nine million years ago, the earth's crust broke into two rectangular blocks along the Teton fault, a 40-mile long zone of weakness. Through sporadic movements, the western block hinged skyward to become the Teton Range, while the eastern block tilted downward to form the valley called Jackson Hole. The valley sank four times more than the mountains rose. Displacement continues, and an earthquake-producing movement along the fault can occur at any time.
Shaping the Mountains: Erosional forces continually shape the rising mountains. Wind, water, ice, and glaciers, particularly of the last Ice Age, shaped the range into today's skyline. The sedimentary rock layers that covered the central peaks have been worn away, but mountain building continues, counteracting erosion.
Teewinot: The Shoshone called the Teton Range "Teewinot," meaning many pinnacles. Other Native Americans called the snow-capped peaks the "Hoary Fathers."
Naming the Range:
In the 1800s, explorers referred to the Tetons as the "Pilot Knobs," guiding their expeditions. On a clear day, the Tetons are visible from 150 miles in every direction. French Canadian fur trappers, approaching from the west, named the tallest peaks "Les Troit Tetons" -- the three breasts. Today the Range itself and three separate peaks -- Grand Teton, Middle Teton, and South Teton -- bear this name.