Tracing Big Sky Footsteps:

The Lewis and Clark Expedition and Its Enduring Legacy in Montana

Long before Montana was stitched into the fabric of the United States as the 41st state, its wide river valleys and silent mountain passes bore witness to a voyage that would forever redefine the American imagination. In the early decades of the nineteenth century, when the Missouri River flowed swift and free under an open sky, the Corps of Discovery—led by Captain Meriwether Lewis and Lieutenant William Clark—pierced the great western wilderness. Their passage through what would one day be Montana was not merely a geographic traversal but a profound encounter of cultures, landscapes, and histories that would echo through generations.

This tale of discovery, adversity, and transformation would later become a cornerstone of Montana’s historical identity. More than a mere footnote in the broader narrative of westward expansion, the segment of the Lewis and Clark Expedition that wound through Montana left indelible imprints on the land, its indigenous inhabitants, and the collective memory of the nation.

The Journey into Montana: Charting the Unknown

Commissioned by President Thomas Jefferson in 1803, the Corps of Discovery set out from St. Louis with the grand purpose of exploring the newly acquired Louisiana Territory. Their mission was simultaneously scientific, diplomatic, and strategic: to map the land, document its resources, and establish American presence before European powers could stake competing claims. The expedition’s advance up the Missouri River marked the opening of a vast terrain that had never before been documented by Euro-Americans, even though the lands had long been home to indigenous peoples. 

When Lewis and Clark crossed into what is now Montana in the spring of 1805, they entered a world of dramatic contrasts—furious river currents, vast plains shimmering in golden grasses, and the distant silhouettes of the Rockies standing like sentinels against the sky. The expedition’s journals overflowed with wonder at the sights they encountered, from herds of bison roving the plains to the Great Falls of the Missouri, which challenged them with gruelling portages. 

Encounters and Exchanges: Indigenous Peoples and the Corps of Discovery

No account of the Corps’ Montana passage is complete without acknowledging the intricate web of relationships they encountered among Native American nations. At the headwaters of the Missouri near present-day Three Forks, the confluence of the Jefferson, Madison, and Gallatin rivers was more than a geographical curiosity—it was a cultural crossroads. For millennia, tribes such as the Blackfeet, Salish, Crow, and Shoshone had traversed and stewarded these lands. 

Amid these relationships, none was more consequential than that with the Shoshone woman Sacagawea, whose presence with the Corps stands as both a human story of resilience and a symbolic bridge between cultures. Born near the headwaters around 1788, she had been taken from her people as a child and later reunited with them while guiding Lewis and Clark across the Continental Divide. It was Sacagawea who recognized landmarks such as Beaverhead Rock, a massive sandstone formation that she knew from her youth. Her recognition signaled the proximity of her people and soon led to the acquisition of horses essential for traversing the mountains ahead. 

Beaverhead Rock thus stands as a testament not only to the expedition’s geographical progress but to the invaluable indigenous knowledge that made their crossing possible. This landmark—later preserved as Beaverhead Rock State Park and listed on the National Register of Historic Places—remains a silent witness to the union of memory and meaning along the Lewis and Clark trail. 

Geographic Marvels and Scientific Record

Beyond interpersonal encounters, Montana gifted the expedition with some of its most breathtaking and scientifically significant observations. In July 1805, as the Corps sailed through a narrow canyon north of Helena, Meriwether Lewis was struck by the immense limestone cliffs that framed the Missouri River. He dubbed this entrancing corridor the “Gates of the Mountains.” Its towering rock walls, rising over a thousand feet above the water, were unlike anything previously recorded in their journals, evoking awe and reverence. 

The expedition meticulously chronicled the landscapes they traversed—the arid breaks of the upper Missouri, the rich biodiversity of the river valleys, and the changing constellations overhead. These records would become foundational in the growing body of American geographic and natural history. Botanicals, animal species, and geological formations encountered in Montana contributed to the Corps’ broader catalog of new discoveries. 

Pompeys Pillar: A Carved Legacy

Perhaps the most enduring physical trace of the expedition in Montana is found at Pompeys Pillar, near present-day Billings. On July 25, 1806—during the Corps’ return from the Pacific—William Clark ascended a remarkable sandstone outcrop rising above the Yellowstone River. From its summit, he inscribed his name and date into the rock. This solitary signature endures as the only verified physical inscription made by members of the Lewis and Clark Expedition that survives today. 

Clark’s naming of the outcrop—initially “Pompey’s Tower” for Sacagawea’s infant son Jean Baptiste, nicknamed “Pomp”—binds together personal attachment with geographical memory. Pompeys Pillar, now a National Monument, stands as a place of reflection—where the vast sweep of the American West and the intimate markers of human passage converge. 

Montana in Context: The Corps’ Enduring Footprint

The Lewis and Clark Expedition spent more of its journey within Montana’s future borders than in any other state. According to historical summaries, the party’s time in the region spanned nearly a quarter of their overall expedition timeline. 

Montana’s rivers and ridgelines shaped the experience of the Corps as much as they shaped the geographic identity of the nascent United States.

The legacy of this journey reverberates in Montana’s cultural topography. Towns like Three Forks cherish their connections to the expedition—the Mississippi and Missouri tributaries that converge there bear the names bestowed by Lewis in honor of national leaders. 

Numerous parks, museums, and interpretive centers, such as the Lewis and Clark Interpretive Center in Great Falls, celebrate the expedition’s narrative, preserving artifacts, maps, and stories that draw countless visitors each year. 

Montana’s place names, too—Lewis and Clark National Forest, Lewis and Clark County, and Pompeys Pillar—serve as daily reminders of the Corps’ passage and its imprint on the collective landscape. 

Reflection: The Expedition’s Dual Perspectives

To view the Lewis and Clark Expedition through a modern lens is to recognize both its remarkable achievements and its complex consequences. On one hand, the Corps opened paths of scientific inquiry, laid the groundwork for geographical understanding, and deepened the young nation’s sense of itself as continental in scope. Their journals offered some of the earliest written documentation of Montana’s geology, flora, and fauna, capturing moments of sublime natural beauty alongside pragmatic survival. 

Yet this narrative also carries shadows—the inevitable collision between expanding American interests and the sovereign lives of indigenous peoples whose histories in these valleys extend back millennia. The expedition’s proclamations of sovereignty and symbolic ceremonies with flags and medals marked the beginning of a profound upheaval in the lives of the tribes who called these lands home. 

Montana’s interpretation of the Lewis and Clark story continues to evolve, embracing a fuller spectrum of voices—acknowledging the invaluable contributions of indigenous guides, interpreters, and knowledge keepers such as Sacagawea and her Shoshone relations. These narratives layer the remembered past with richer nuance, honoring both discovery and the deep roots already present in the land.

Conclusion: Memory Carved in Stone and River

In the vast tapestry of Montana history, the Lewis and Clark Expedition occupies a central and nuanced place. It was a journey of geography and human encounter, of hardship and hope, and of names given and landscapes reshaped. From the headwaters of the Missouri to the sun-burnished sands of Pompeys Pillar, the traces of the Corps’ passage endure in stone, in river bend, in place name, and in story.

The legacy of Lewis and Clark in Montana is not static; it is living memory—etched in the heart of Big Sky country, whispered by prairie grass, and carried forward by the many voices who continue to tell this tale. It is a legacy that invites reflection: on the remarkable courage it took to chart the unknown, on the cultures whose knowledge made that charting possible, and on the enduring landscapes that continue to inspire wonder in all who follow the rivers west.

Works Cited

Bureau of Land Management. “Pompeys Pillar History.” Pompeys Pillar National Monument, U.S. Department of the Interior. 

“Beaverhead Rock State Park.” Montana Fish, Wildlife & Parks. fwp.mt.gov

“Gates of the Mountains.” Discover Lewis & Clark. 

“Lewis and Clark Expedition.” Encyclopedia Britannica, 2 Dec. 2025. 

“Lewis and Clark Interpretive Center.” Visit Montana. visitmt.com

“Lewis and Clark National Forest.” Wikipedia. 

“Lewis and Clark Expedition.” Wikipedia.