Pompey's Pillar:

A Stone Chronicle on the Yellowstone

There are places in the landscape that read like a slow, patient book — pages weathered by wind and hand, margins annotated by strangers across centuries. Pompey’s Pillar, that solitary sandstone monolith on the south bank of the Yellowstone River in south-central Montana, is one of those places: a column of stone that has borne witness to hunting parties, councils, explorers, settlers, and the private scripts of thousand-year lives. Standing roughly a hundred and fifty feet above the river and occupying about two acres at its base, the Pillar is modest in acreage but immense in historical resonance. 

A rock as crossroads

Long before maps named highways and counties, Indigenous peoples recognized this outcropping as a meaningful place — a landmark, a shrine, a lookout — with the Crow (Apsáalooke) among those who held the Pillar in cultural memory. The Apsáalooke name Iishbíiammaache, often rendered “Where the Mountain Lion Lies” or “Mountain Lions Lodge,” speaks to the spiritual topography that European eyes could not at once see. Archaeological and ethnographic evidence now suggests human activity here stretches back more than eleven thousand years: hunting camps, rock art, ritual use, and the steady accretion of marks that make the face of the Pillar a palimpsest of lives. For people moving along the Yellowstone valley, the Pillar was both compass and cathedral. 

William Clark’s single surviving autograph

If the Pillar’s many names testify to a layered past, no single inscription has done more to fix the site in the American imagination than the scrawl of Captain William Clark. On July 25, 1806, while a detachment of the Corps of Discovery retraced the Yellowstone, Clark climbed the rock and carved his name and date into the soft sandstone. That signature — the only remaining physical inscription by any member of the Lewis and Clark Expedition still intact on the trail — transformed the local landmark into a national icon: the tangible handshake between the myth of an exploring republic and a place already heavy with other histories. Clark’s note also recorded his naming for Jean Baptiste Charbonneau (the infant son of Sacagawea), whom he had nicknamed “Pomp” — the origin of the feature’s familiar Anglo name. 

The historical import of Clark’s inscription is complex. To many Euro-American audiences it became proof: of presence, of discovery, of an expedition’s reach. To the Indigenous people whose lives and marks predated Clark’s by millennia, it was an addition to an already crowded register. Seen together — the petroglyphs, pictographs, pioneer etchings, and Clark’s signature — the Pillar reads like a contested ledger, one that catalogs encounter, memory, and the sometimes uneasy overlay of narratives. 

Geology and the slow work of time

Beneath the human stories is another archive: stone. Geologists trace the Pillar’s bones to Upper Cretaceous sandstones — deposits laid down tens of millions of years ago that were later sculpted by river meanders and erosion into the detached outcrop we see today. Studies suggest the formation was once continuous with nearby bluffs, separated as the Yellowstone cut new channels and floods isolated a block of rock that now stands solitary against the open sky. This deep time underwrites the Pillar’s role as a durable stage for human drama: the same erosional patience that shaped the stone also preserved the very surface upon which letters and figures could be incised. 

From frontier landmark to public memory

Throughout the nineteenth century, the Pillar accumulated a new set of marks: the initials of travelers, names cut by steamboat crews and railway surveyors, and later, the graffiti of tourists. These additions tell another American story — the democratization of travel and the rise of a frontier popular culture that sought to leave its signature on the land. The railways and later the automobile age made the Yellowstone corridor one of movement and commerce; the Pillar, visible from a distance, became a place where the private impulse to be remembered found a public surface. Over time, conservation and interpretation moved to reconcile the site's multiple histories: the Pillar was at once an archaeological site, a Lewis and Clark landmark, and a locus of local memory. 

By the late twentieth century, formal recognition followed public interest. Designated a National Historic Landmark in the 1960s and later protected as Pompeys Pillar National Monument in 2001, the site’s stewardship shifted toward preservation, interpretation, and an attempt — imperfect but earnest — to give equal weight to its Indigenous, exploratory, and settler pasts. Today the Bureau of Land Management manages the monument, supported by friends’ groups and local advocates who prize both its tangible inscriptions and its quieter spiritual resonances. 

Reading the rock: inscriptions, petroglyphs, and ethics

Walking the boardwalk that leads to the top of the Pillar is an act of reading — not merely of letters but of context. Clark’s neatly carved signature sits within a wider field: images of animals, abstract motifs, and the blunt initials of nineteenth-century travelers. Each mark invites questions: who made it, why, and what did it mean then? Modern site managers face a particular ethical knot: how to conserve a surface that is itself a record of many cultures, some of whom consider parts of the site sacred, while also preventing further vandalism or careless “souvenir” carving. Interpretation at the visitor center and on the trail now emphasizes stewardship, Indigenous voices, and the need to see Clark’s signature not as the final word but as one line in a long conversation. 

The Pillar in regional identity and tourism

For Yellowstone County and the surrounding plains, Pompey’s Pillar has become a cultural anchor. It offers a dramatized, almost tactile encounter with national myth — Lewis and Clark are not only names in a book but a visible, human trace at the site — and it also provides a quieter satisfaction: the sweep of the river valley from the Pillar’s summit, the smell of cottonwood, the low, long horizon of Montana. Local groups have built interpretive centers and programs that connect schoolchildren to the landscape and encourage visitors to reflect on continuity rather than conquest. The result is a living heritage site that balances tourism with local meaning. 

Layers of memory and the politics of naming

Names carry power. “Pompeys Pillar” — a transcription of Clark’s private epithet for Charbonneau’s son — masks other nomenclatures and other claims. The Apsáalooke name and its resonance challenge simple narratives of discovery. When historians and local stewards present the Pillar’s story now, many deliberately foreground Indigenous histories, pointing out that Clark’s signature is not a founding act but an entry in an already-long ledger. This reframing is part of a larger effort across the American West: to see national myths in a more polyphonic light and to let place be the teacher rather than merely the backdrop for a single story. 

Preservation as an act of remembering — and forgetting

Preserving Pompey’s Pillar requires choices about what to display, what to protect, and what to let fade. Conservators have stabilized the Clark inscription, installed boardwalks to limit direct contact with vulnerable surfaces, and produced interpretive materials that try to contextualize every mark. At the same time, preservation necessarily involves erasures: cement, protective barriers, and curated narratives can marginalize some voices even as they amplify others. The ethical challenge is to steward the Pillar in a way that honors the multiplicity of its human witnesses — the hunter who left a pictograph, the mother who paused here generations ago, the modern visitor who reads Clark and then looks out across the river and remembers the land itself. 

Why Pompey’s Pillar still matters

In an age of instantaneous images and curated feeds, Pompey’s Pillar resists easy consumption. Its scale is human; one can climb it, touch it (within limits), and read handwriting that was pressed in by a man who lived two centuries ago. Yet the Pillar’s deeper claim is not to celebrity but to continuity: it is a surface where time layers itself legibly. The monument asks us to practice a different habit of attention — one that reads weathering as a kind of language and understands that history is rarely linear. The Pillar’s petroglyphs teach us that landscapes are archives, and the human impulse to leave a name is as old as migration. In that sense, standing at Pompey’s Pillar is less about honoring a single moment in 1806 and more about acknowledging the long human story the rock records. 

A final thought

Travelers who pause at Pompey’s Pillar often speak of silence: not emptiness, but the hush that arrives when a place refuses to be reduced to one tale. The Pillar keeps its inscriptions like stones keep river shadows — each delicate, each transient, each part of a larger form. If history is a conversation across time, then Pompey’s Pillar is a particularly eloquent interlocutor: patient, weathered, and insistent that we read closely, listen widely, and remember that every signature is also a reply to somebody else’s mark. 

Selected sources and further reading

National Park Service — Pompeys Pillar overview and significance. 

Bureau of Land Management — Pompeys Pillar National Monument (visitor information and cultural context). 

Friends of Pompeys Pillar — local history and interpretive projects. 

National Register/NPS historic resource study (pdf) — geological and archaeological background. 

Montana Bureau of Mines & Geology — geological interpretation and landscape evolution. 

Historic Montana — National Historic Landmark entry, Indigenous place-names and cultural context.