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Pompeys Pillar National Monument

Pompeys Pillar National Monument in Montana. Bureau of Land Management.
Pompeys Pillar National Monument in Montana. Bureau of Land Management.
Established: 2001
Location: 25 miles east of Billings, Montana along the Yellowstone River
Size: 51 acres

Towering more than 100 feet over the bank of Montana's Yellowstone River and covering two acres at its base, massive Pompeys Pillar is not only visually striking, but an unusual historical landmark: its rock faces hold a vivid history of the unfolding American west.

The sandstone pillar bears early Native American drawings as well as Captain William Clark's inscription from 1806-the only physical evidence remaining along the now-famous expedition route of explorers Lewis and Clark. During his return trip to St. Louis, Clark climbed the Pillar and carved his signature and the date, July 25, 1806, in the sandstone. He noted in his journal, "This rock I ascended and from its top had a most extensive view in every direction on the Northerly Side of the [Yellowstone] river...". Clark also described an idyllic landscape of grassy plains, snow-capped mountains, and cliffs abutting the wandering river, and his own discovery of a fish cemented in the face of the rock. Clark named the butte "Pompy's Tower" after the infant son of Sacagawea--the Shoshone woman who accompanied Lewis and Clark--whom Clark called "Pompy." An expedition biographer changed the name to Pompeys Pillar in 1814.

In addition to William Clark's signature, Pompeys Pillar has served as a registry for Native Americans, fur trappers from the 1800s, and missionaries, railroad workers and settlers from the late 19th century. The sandstone is marked with hundreds of their etchings and drawings.

More about the Monument

The butte dates from the last strata of the Cretaceous Period (75-65 million years ago). Nearby sandstone formations contain fossilized ruins of dinosaurs and primitive mammals.

Situated a natural ford in the Yellowstone River, the Pillar and the surrounding 51 acres that are part of the Monument have long been a crossroads for hunters and their prey; the once-prominent buffalo herds crossed the Yellowstone at the Pillar, along with elk, wolves and deer. Today, coyotes, raccoons, and numerous other small mammals, including the endangered black-footed ferret, make their homes in the region. The riparian corridors along the Yellowstone River provide food and shelter for more than 100 bird species, including waterfowl, songbirds, shorebirds and threatened or endangered birds such as the ferruginous hawk, the loggerhead shrike, the peregrine falcon and bald eagles. Today, the ecosystem at the Pillar is much the same as it was when Lewis and Clark encountered it almost 200 years ago.

The Crow Indians, who refer to Pompeys Pillar as "the place where the mountain lion lies" or "the mountain lion's lodge" because of the natural head of a lion in the sandstone, still use the pillar for spiritual journeys and as a prayer site. Prehistoric pictographs and petroglyphs blanket the walls of Pompeys Pillar, providing a visual story of the Crow Indian's spiritual connection with the pillar.

Below ground in the area of Pompeys Pillar is archaeological evidence of past occupation going back more than 11,000 years. These materials appear to be the remains of hunting and living camps, probably occupied by relatively small groups of people for short times. The remains of butchered bison and other animals, along with mussel shells from the nearby Yellowstone River, are scattered among flaked stone tools and debris around small surface hearths. The ancient camps were buried by slow-moving flood waters soon after abandonment; later occupations settled on the new, higher surfaces.

Pompeys Pillar was declared a National Monument in 2001 by presidential proclamation under the Antiquities Act. Prior to its monument status, it was designated a National Historic Landmark in 1965. Today, the Monument is also a symbolic and important stop along the 3,700-mile Lewis and Clark National Historic Trail, another part of the National Landscape Conservation System.

Threats to Pompeys Pillar National Monument

The Monument receives more than 50,000 visitors a year, most of whom are well-meaning; some, however, deface the rocks, touch petroglyphs, or remove ancient artifacts. The BLM lacks adequate staff for visitor education and vandalism control; budget constraints limit the monument to one full-time, year-round employee and some additional summer staff. Although the Pillar is most popular with visitors in the summer, continual supervision and visitor outreach within the area, which includes 431 acres and one and one half miles of the Lewis and Clark Historic Trail, is necessary year-round.


Pompeys Pillar Visitor Center: 406-875-2233
Bureau of Land Management
Pompeys Pillar Historical Association

Updated December 2003