The Pillar overlooks the Yellowstone River about 25 miles east of Billings, Montana. The area is easily accessible from Interstate 94, using exit 23, or from Montana Highway 312. The Pillar is a sandstone butte or mesa and covers about two acres at its base and stands about 150 feet high. Because it is the only sandstone outcrop on the south side of the Yellowstone River for several miles in either direction, it has been a landmark for centuries.
Pompeys Pillar is at a natural ford in the Yellowstone River. In addition, the mouth of Pompeys Pillar Creek on the north side of Yellowstone and the mouth of Fly Creek on the south form natural passageways leading to the river ford at Pompeys Pillar. As a result, the area has been a crossroads throughout history for hunters and their prey such as the once-prominent buffalo herds. In addition to Clark’s signature, the sandstone is marked with literally hundreds of other etchings and drawings. Clark noted evidence of Native American use, “The Indians have made 2 piles of Stone on top of this Tower. The nativs have ingraved on the face of this rock the figures of animals....” Fur trappers of the early 1800s, military expeditions, railroad workers, and early settlers used the sandstone as a registry of their passing. In a very real sense, Pompeys Pillar’s sandstone facets hold a vivid history of the unfolding West.