Land of Many Uses / Lewis and Clark Reach the Rapids

By editor

Shonkin, Chouteau County, Montana

On the morning of June 13, 1805, Meriwether Lewis and a small party of four men traveled westward along the south bank of the Missouri River, their ears pricked by a distant roar that grew steadily louder. At first it was a faint murmuring, like the sound of wind through distant trees or the faint rush of a creek. But as they pressed forward across the undulating plains and coulees near what is today Shonkin, Montana, the sound sharpened into a thunderous cascade. When Lewis crested the final ridge before the river, he was confronted by a spectacle of nature’s raw power -- a succession of five waterfalls tumbling more than 400 feet over a ten-mile stretch. The Great Falls of the Missouri River sprawled before him, a scene he later described in his journal as “a sublimely grand spectacle,” one that captivated his senses and marked a crucial waypoint on the expedition.

The Great Falls are not a single cataract but a series of five distinct drops: Black Eagle Falls, Colter Falls, Rainbow Falls, Crooked Falls, and finally the Great Falls proper. Each plunge cuts through layers of Precambrian Belt Supergroup rocks, some nearly 1.4 billion years old. These sedimentary formations, composed of argillites, quartzites, and dolomites, tell a story of ancient seas and tectonic upheavals long vanished from the land. The Missouri River here slices a deep gorge through these resistant rocks, carving out ledges and plunge pools that shimmer with spray and rainbows in the sunlight. The sound of the falls is relentless, echoing off the surrounding cliffs and rattling the bones.

Before this moment, the expedition had been delayed and uncertain. For days, Lewis and Clark had debated which fork of the river was the true Missouri. At the confluence downstream, they had encountered the Marias River, a broad northern branch, which many of the men mistook for the main river. However, Lewis and Clark trusted the reports of local Native American tribes and their own observations, believing the southern fork to be the Missouri’s principal channel. When Lewis first heard the roar of the falls, it confirmed their choice. The Marias lay some fifty miles downstream, a river without the dramatic cascade that would mark the true Missouri’s path.

Yet the Great Falls presented a daunting obstacle. The river was no longer navigable by their keelboats or dugout canoes. The expedition faced a nearly insurmountable barrier that forced them to unload and carry their boats and supplies overland around the falls. This portage, extending approximately eighteen miles, consumed nearly a month of grueling labor. The men fashioned rudimentary wheels from cottonwood logs, which groaned under the weight of their vessels as they rolled the boats across uneven prairie grass and rocky ridges. The soil here consists primarily of glacial outwash deposits and loess, the windblown silt that blankets much of central Montana, supporting mixed-grass prairies of blue grama (Bouteloua gracilis), needle-and-thread grass (Hesperostipa comata), and scattered clumps of prairie junegrass (Koeleria macrantha).

The portage route itself weaves through coulees and ridges carved by ancient glacial meltwaters, a reminder of the Pleistocene epoch’s shaping hand. The area around Shonkin is also notable for the Shonkin Sag, a large glacial meltwater channel that funnels water southward from the Rocky Mountain front. This geological feature contributed to the formation of the river’s course and the falls themselves.

The men’s progress was slow and taxing. Lewis recorded in his journal the monumental effort involved: “The portage of the boats about the great falls is very tedious and laborious. The men are much fatigued.” Clark, ever pragmatic, organized the labor with military precision, but even so, the intense sun, biting insects, and rugged terrain tested the party’s endurance. The month-long detour around the Great Falls constituted one of the most physically demanding sections of their entire journey.

Despite these hardships, the expedition’s scientific curiosity remained keen. Lewis took careful note of the flora and fauna, describing specimens they encountered. Along the riverbanks, cottonwoods (Populus deltoides) and willows (Salix exigua) provided shade and shelter for wildlife such as mule deer (Odocoileus hemionus) and beaver (Castor canadensis). The air was punctuated by the sharp cries of the western meadowlark (Sturnella neglecta) and the occasional sight of a bald eagle (Haliaeetus leucocephalus) soaring above the falls’ misty veil.

The land around Shonkin today continues to support a diversity of uses, managed by the U.S. Forest Service for grazing cattle, preserving wildlife habitat, and offering recreational opportunities. This multifaceted stewardship reflects a continuity of human interaction with the landscape that stretches back thousands of years before Lewis and Clark’s arrival. Indigenous peoples long adapted to the rhythms of the plains and river, hunting bison, gathering wild plants, and navigating the waterways. The modern Sulphur Springs Hiking Trail follows a portion of the route Lewis followed on that June morning, inviting visitors to step into the same prairie grasses and coulees where those first explorers stood.

The Great Falls and their surrounding lands exemplify a landscape formed by profound geological time and shaped by successive waves of human use. Lewis’s words capture the moment’s significance: “The appearance of the river below the falls is truly grand, and the roar of the water is heard at a great distance.” His journal entries give us a glimpse of the awe inspired not by vague sentiment but by the tangible force and structure of nature itself.

In this region, the Missouri River’s course and the ancient rocks beneath it narrate a story of earth’s slow but relentless change. The Great Falls mark a boundary where the river’s energy is released in sudden, dramatic descent, a natural barrier that shaped the expedition’s path and the course of exploration in the American West. The portage here was more than a physical challenge -- it was a moment when human determination met the enduring power of the land.

Today, the Great Falls remain a crucial landmark along the Lewis and Clark National Historic Trail, a place where visitors can witness the same geological grandeur and ponder the struggles and discoveries of those who traveled here more than two centuries ago. The land’s many uses -- from grazing cattle to preserving habitat to offering solitude for hikers -- continue the story of human engagement with this remarkable landscape.

See also

• Land of Many Uses / Lewis and Clark Reach the Rapids at Shonkin, Chouteau County
• Lewis and Clark National Historic Trail at Loma, Chouteau County
• An Island on the Plains at Big Sandy, Chouteau County