In this picture they pause at the confluence of the Salmon and Snake Rivers in Hells Canyon, the serpentine gorge that forms the boundary between the states of Idaho and Oregon. The Salmon River -- "The River of No Return" -- drains a large, scenic, and lightly populated area of central Idaho. Had the Lewis and Clark expedition in 1805 chosen to float the Salmon River west across Idaho, instead of heading north by horse and proceeding overland through Lolo Pass, this is where it would have come out -- if somehow it had managed to survive the wild waters of this river.
The federal government in the nineteenth century defined a frontier as any part of the United States containing fewer than two people per square mile. Curiously, by that measurement Idaho in the year 2000 remains at least 40 percent frontier, and much of that land lies within the watershed of the Salmon River. With slightly more than one million residents, Idaho remains so lightly populated today that the city of San Diego, California, alone contains more residents.
