View northward down the valley where the Corps of Discovery established the camp they occupied from the 17th until the 24th of August, 1805. Here Red Rock River and Horse Prairie Creek join to form the Beaverhead River, which Lewis and Clark considered to be the upper part of "Jefferson's River." Armstead, founded in 1907, was named for Harry Armstead, who developed a silver mine 35 miles northeast of here. In 1910 it became the eastern terminus of the Gilmore and Pittsburgh Railtoad, which crossed the divide into the Lemhi Valley at Bannack Pass. In 1963, when Clark Canyon Dam was completed, the site of Armstead was submerged beneath the reservoir.
Lewis took special note of the landmark at left of center, the tip of which is now Armstead Island in Clark Canyon Reservoir. "Immediately in the level plain between the forks," he wrote, "and about 1/2 a mile distance from them stands a high rocky mountain, the base of which is surrounded by the level plain; it has a singular appearance." (See Clark's map.)
"I do not beleive," Lewis wrote upon arriving at the "forks of the Jefferson" on August 10, 1805, "that the world can furnish an example of a river runing to the extent which the Missouri and Jefferson's rivers do through such a mountainous country and at the same time [be] so navigable as they are. If the Columbia furnishes us such another example," he continued,"a communication across the continent by water will be practicable and safe."1
By the time the Corps of Discovery pitched camp2 at the confluence of Horse Prairie Creek and Red Rock River on that sunny August day in 1805, even the enlisted men could have testified that the Missouri was not "navigable" all the way to its source, Lewis's extravagant metaphor notwithstanding.
The fantasy would continue to unravel. Next would come the discovery that the situation was no better on the Columbia's upper reaches, and in fact was much worse. That would be followed by an unforgettable scramble across the Bitterroot Mountains. The last chapter, a foam-soaked, bone-jarring descent of three rock-strewn western rivers—the Clearwater, Snake and Columbia—to tidewater would close the book on the fabled "Northwest Passage" forever.
Jefferson had instructed him to find the river that would "offer the most direct & practicable water communication across this continent for the purposes of commerce."3 Lewis confirmed in his first glance westward from the crest of the Rockies that no such waterway existed. At the close of the expedition he reported to the President only that he had indeed discovered the most "practicable route," but that "the most formidable part" was a portage of 340 miles, including "140 over tremendious mountains" that were passable for only about three months of the year.4 In fact, he admitted, for the transport of "bulky or brittle" commodities from the East Indies to the U.S. and Europe it would "never be found equal on an extensive scale to that by way of the Cape of Good hope." But given sufficient government subsidy, he added—as if he were thinking of Jefferson's political opponents—he was "fully convinced that...in the course of ten or twelve years a tour across the Continent by the rout mentioned will be undertaken by individuals with as little concern as a voyage across the atlantic is at present." All of those thoughts may have begun to take shape in his mind well before he reached the "forks of the Jefferson." What forms and feelings they evolved through during the next forty days has been left for us to imagine.
View from Armstead Island, c. 1960
This view looks southeast from the middle knob on the south slope of Armstead Hill (see preceding photo). The Red Rock River meanders through the plain, its freedom severely restricted by highways and railroad grades. The section of U.S. Highway 15 shown here began in 1864 as a privately-owned toll road. As Interstate 15, it now connects Lethbridge, Alberta with Los Angeles, California. To the right of the highway on the near horizon are the Tendoy Mountains, dominated by sharp-pointed Garfield Mountain (el. 10,961 ft.). At center on the horizon is the Centennial Range, whose highest ridges bear the Continental Divide and also define the southwestern boundary of the state of Montana.
1. The American essayist Elbert Hubbard (1856–1915), in a different connection, characterized such overweening optimism as "a kind of heart stimulant—the digitalis of failure."
2. The name of this bivouac, which now is commonly written "Camp Fortunate," appeared only on Clark's map as "Fortunate Camp." We choose to use Clark's expression here for the benefit of the semantic subtlety it conveys. It was never used in either form in any of the journals.
3. Donald Jackson, ed., Letters of the Lewis and Clark Expedition with Related Documents, 1783–1854 (rev. ed., 2 vols., Urbana: University of Illinois Press, 1978), 1:61.
4. Ibid., 1:320. For another assessment of Lewis's claim, see Jackson, 1:324, note 1.
Funded in part by a grant from the Montana Committee for the Humanities.