The general surface of Idaho is extremely mountainous and broken. Between the meridians 110 and 118, a distance of 500 miles, there is a range of mountains on an average of every 10 to 20 miles.

The Teton Mountains are in Wyoming, but we have always had at least a quasi interest in them; no illustrated treatise on the physiography of Idaho omits the picture of those sublime summits. Idaho Territory at first included them; their melting snows contributed to our irrigation; they are inseparable from our early history, and their morning shadows fall over a vast section of our state. They were beyond doubt discovered by John Colter in 1808, but are first mentioned in recorded history in Washington Irving’s “Astorians”, as having been seen by Wilson Price Hunt on September 15, 1811. Hut gave them the name of “Pilot Knobs”; the Indians called them “Tee-win-at”, the pinnacles; French trappers were responsible for their present name by christening them Trois Tetons”, the three breasts.




Sources:
"Idaho: The Place and Its People" by Bryon Defenbach
"History of Idaho" by James H. Hawley