Lewis and Clark Portage Route

By editor

Great Falls, Cascade County, Montana

In the summer of 1805, the Missouri River--usually a restless, tumbling artery carving its way eastward--presented a formidable barrier to the Corps of Discovery. Just north of what is now Great Falls, Montana, the river plunges over a series of cataracts and churning rapids, a sequence of cascades spanning nearly ten miles and dropping over 600 feet in elevation. Faced with this unyielding chain of waterfalls, Meriwether Lewis and William Clark resolved to haul their canoes and gear around the entire obstacle--a portage that would test their endurance, ingenuity, and resolve.

The men established two main camps to manage this daunting task. The lower camp lay roughly twelve miles northeast of the present highway crossing, situated near a wide bend of the Missouri where cottonwood trees flourished along the floodplain. Here, the voyageurs and soldiers felled slender stands of Populus deltoides--cottonwood--fashioning crude wagons. The wheels were cut directly from the tree trunks, their wooden rims rough-hewn but serviceable. These rudimentary carts were essential to move the heavy canoes--each weighing hundreds of pounds--and the tons of supplies necessary for the expedition’s survival.

The upper camp rested about five miles southwest, nestled near a cluster of islands in the river historically known as the Bear Islands. These islands took their name from the Ursus americanus--American black bears--that frequented the dense riparian forests. The men’s proximity to these bears added an element of wild unpredictability to their arduous labor.

Between these camps, the crew hauled their gear across an expanse of plains and badlands under the oppressive June sun. The landscape was no less challenging than the river itself. The ground was carpeted with Opuntia polyacantha, the plains prickly pear cactus, whose flattened pads bristled with sharp spines. These spines shredded the moccasins of the men, who wore simple leather footwear ill-suited for the thorny undergrowth. Rattlesnakes, likely Crotalus viridis--the prairie rattlesnake--lurking beneath the brush, struck at their feet, adding danger to every step.

The geological stage for this portage was set by a series of sedimentary layers deposited over millions of years. The Missouri River, tracing a path through the Highwood Mountains and the Little Belt Range, had carved through Cretaceous sandstones and shales. The falls themselves mark a line where resistant Madison Limestone, formed some 350 million years ago in a shallow tropical sea, meets softer formations downstream. The relentless flow over these rocks created the cascade system that forced the expedition’s detour.

William Clark, ever meticulous in his journals, lamented the ordeal with stark candor: "The portage was near man-killing. The men has to haul with all their strength wate & art," he wrote on July 4, 1805. His words convey not only the physical exhaustion but the mental strain wrought by the relentless effort. The phrase "strength, wate and art" encapsulates the mixture of brute force, weight, and the clever contrivances--like the cottonwood-wheeled wagons--needed to accomplish the task.

The heat was oppressive. Daytime temperatures in early summer often climbed into the 90s Fahrenheit (mid-30s Celsius), and the men had no shelter from the relentless sun. They were compelled to work from dawn until dusk, pausing only briefly to drink from the river or to rest aching muscles. The sweat of the men mingled with the dust of the plains, their bodies smeared with the grime of the land.

This portage was not merely a logistical hurdle; it was a profound encounter with the natural forces shaping the continent. The Missouri’s waterfalls had been carved during the rebounding of the earth’s crust following the last glaciation. The Laurentide Ice Sheet, retreating some 12,000 years ago, had altered the river’s course and increased its erosive power. The expedition’s passage through this geologically active landscape was a crossing of deep time.

The route they took is now traced by the Lewis and Clark National Historic Trail, which threads through the modern city of Great Falls. The urban landscape overlays the plains where the men struggled, though the river’s cataracts remain unchanged in their rugged majesty. The trail connects the two campsites, allowing travelers today to walk in the footsteps of those who carried their canoes through the heat, thorns, and rattlesnakes.

On the return journey in 1806, the expedition retraced the same grueling portage. The hardships endured here exemplify the expedition’s broader challenge: to push forward into an unknown continent, relying on the resilience of men and the keen observation of the natural world. Lewis himself remarked on the significance of their task, noting that the portage "required all the exertions of the men and the ingenuity of the officers." His observation underscores the blend of physical labor and problem-solving that defined the Corps of Discovery.

The natural environment of this portage remains striking. Cottonwoods continue to line the Missouri’s banks, their broad leaves trembling in the wind and providing scarce shade. Prickly pears bloom with bright yellow flowers in early summer, while the occasional prairie rattlesnake slithers silently beneath the brush. The river’s roar at the falls is a constant reminder of the power that once forced men to carry their canoes across the plains.

This episode in the expedition’s journey reveals much about the interplay between geography and human endeavor. The men were compelled by the river’s geology to leave the water and travel overland, negotiating a landscape sculpted by ancient seas and recent glaciers. Their struggle was both physical and intellectual, demanding strength and innovation in equal measure.

The portage route remains a tangible link to the early exploration of the continent, one that invites reflection on the forces shaping North America’s vast interior. As Clark wrote, the effort was "near man-killing," but it was also a crucial step in opening the path westward, a passage across a land defined by its rugged natural features and the endurance of those who traversed it.

See also

• Lewis and Clark Portage Route at Great Falls, Cascade County
• Lewis and Clark Passed Here at Great Falls, Cascade County
• The Experiment at Great Falls, Cascade County