Lewis and Clark

By editor

Three Forks, Gallatin County, Montana

The Missouri River’s headwaters converge at a place the local Crow called “The Meeting of the Rivers,” where three streams unite to begin a mighty journey eastward. In the summer of 1805, the Corps of Discovery arrived at this confluence--a rugged, windswept landscape carved by millennia of glacial and fluvial forces. Here, the Jefferson, Madison, and Gallatin Rivers join, their waters mingling beneath broad skies that stretch unbroken to the west. The expedition passed this way twice: once on their westward quest in July 1805, and again on their return in July 1806. The contrast between these two passages reveals the transformation of the land from unknown wilderness into familiar terrain, etched deeply into the memory of men who bore witness to its grandeur.

In July 1805, the expedition was beleaguered, their spirits frayed by relentless hardship. The men had struggled for weeks against the Missouri’s shallow, rocky currents, their canoes scraping over sandstone ledges and gravel bars. The river here cuts through rocks of the Belt Supergroup, Precambrian sedimentary formations some 1.4 billion years old, their rusty-red and gray layers tilted by ancient mountain-building forces. These geological formations, exposed along the riverbanks, revealed the deep history of the continent, though to the Corps, they were obstacles to progress.

On July 25, 1805, Captain Meriwether Lewis and William Clark reached the point where the three rivers meet. Clark was suffering from fever, worn thin by the strain of navigating rapids and the ever-present clouds of mosquitoes that swarmed relentlessly. Lewis, ever the geographer and naturalist, took it upon himself to name these tributaries after prominent figures in the young nation: the Jefferson after President Thomas Jefferson, the Madison for Secretary of State James Madison, and the Gallatin for Treasury Secretary Albert Gallatin. Their names endure, a catalog of the expedition’s connection to the fledgling United States.

The Corps needed horses to traverse the rugged mountain passes ahead, guides who could lead them safely through the Bitterroot Range to the Shoshone, whose horses they so desperately required for the next phase of their journey. Lewis recorded the bitter reality of their situation in his journal: “The country is wild and barren but the soil fertile and the game abundant.” Yet the men faced uncertainty, their provisions low, and the harsh Montana summer threatening to close the mountain passes with early snows.

Lewis’s scientific curiosity remained keen even in these dire moments. He observed the flora--ponderosa pine (Pinus ponderosa) and Douglas fir (Pseudotsuga menziesii) forests clinging to the slopes, while the valley floors boasted bluebunch wheatgrass (Pseudoroegneria spicata) and bitterroot (Lewisia rediviva), the latter a plant sacred to many Native peoples. Wildlife was abundant--the tracks of elk (Cervus canadensis) and mule deer (Odocoileus hemionus) marked the soft earth, while the distant calls of mountain bluebirds (Sialia currucoides) punctuated the stillness.

The expedition’s westward passage was one of discovery and trial, the land a vast unknown. Each bend in the river could conceal dangers, each ridge a new challenge. Lewis wrote, “We are entering a country little known to the white man, but one which the native inhabitants prize beyond all others for its abundance.” The Missouri here was still young, fed by snowmelt and springs, carving a path through rocky canyons and open valleys.

Exactly one year later, in July 1806, the expedition retraced its steps back through the Gallatin Valley, but the journey had changed entirely. Clark now rode with twelve men and fifty horses, following an ancient buffalo trail that Sacagawea, their Shoshone guide, had recommended. The once mystifying mountains and valleys were now familiar--a landscape mapped by memory and marked by experience.

Clark’s journal entry from July 14, 1806, describes the Gallatin Valley in terms of its agricultural promise: “The valley is open and well watered, the soil rich and deep, the game plentiful.” These words would prove prophetic, for the Gallatin Valley and its surrounding basin would become one of Montana’s most productive agricultural regions, the soil nourished by the rivers Lewis and Clark named.

The route across the Bridger Mountains, which Clark’s party took, follows a series of passes carved by glaciers during the Pleistocene epoch, some 15,000 years prior. These mountains, part of the Rocky Mountain front, rise sharply from the valley floor, their jagged summits capped with snowfields even in summer. Descending from the Bridger range, the expedition reached the Yellowstone River, where they constructed dugout canoes from cottonwood (Populus deltoides) trunks--light, buoyant vessels suited for the winding river ahead.

Clark’s confidence in the land and its resources reflects the transformation from uncertainty to knowledge. The horses grazed on abundant grasses, and the men hunted bison (Bison bison) that still roamed the plains in vast herds. The buffalo trails they followed had been carved by generations of migratory wildlife, routes now serving the footsteps and hoofbeats of explorers and settlers.

The contrast between the two passages is not merely one of direction, but of experience and understanding. The 1805 journey was a cautious advance into the unknown, marked by hardship and the need to adapt. In 1806, the land was no longer inscrutable wilderness but a landscape known and navigable, its resources mapped and its dangers anticipated. Clark’s return through the Gallatin Valley was not exploration but a return homeward, a retracing of steps with the assurance of familiarity.

It is worth recalling Clark’s own words from his journal, where he remarked on the valley’s promise: “The country is well watered, the soil rich, and the game abundant. I believe this valley will one day support many families.” This observation captures the intersection of natural abundance and human enterprise, a landscape shaped by both geological time and human endeavor.

Today, the rivers Lewis and Clark named still course through Montana’s rugged terrain, their waters fed by melting snow, springs, and tributaries that trace back into the Rocky Mountains. The headwaters region around Three Forks remains a place where the ancient rocks of the Precambrian Belt Supergroup rise in layered outcrops, and where forests of lodgepole pine (Pinus contorta) and quaking aspen (Populus tremuloides) cover the hillsides. The land continues to nurture the wildlife--elk, deer, eagles--that Lewis and Clark noted with such keen eyes.

The expedition’s passage through this country reminds us that the land is a palimpsest of natural processes and human history, written in stone and memory. The names Jefferson, Madison, and Gallatin mark more than rivers--they mark the beginning of a new chapter in the relationship between people and this landscape.

See also

• Lewis and Clark at Three Forks, Gallatin County
• [Headwaters of the Missouri River](/historic-markers/headwaters