Pompeys Pillar

Large rock cliff rising from flat grassy surface

Quick Facts
Yellowstone County, MT
National Register of Historic Places, National Historic Landmark

Lewis and Clark NHT Visitor Centers and Museums

Visitor Centers (shown in orange), High Potential Historic Sites (shown in black), and Pivotal Places (shown in green) along the Lewis and Clark National Historic Trail

Pompeys Pillar is a High Potential Historic Site on the Lewis and Clark National Historic Trail.

On July 25, 1806, while descending the Yellowstone River, Clark “arived at a remarkable rock Situated in an extensive bottom on the Stard. Side of the river & 250 paces from it.” He wrote that, “this rock I ascended and from it’s top had a most extensive view in every direction. This rock which I shall Call Pompy’s Tower [named for Jean Baptiste ‘Pomp’ Charbonneau] is 200 feet high and 400 paces in secumphrance and only axcessable on one Side which is from the N. E the other parts of it being a perpendicular Clift of lightish Co­loured gritty rock on the top there is a tolerable Soil of about 5 or 6 feet thick Covered with Short grass. The Indians have made 2 piles of Stone on the top of this Tower. The nativs have ingraved on the face of this rock the figures of animals &c. near which I marked my name and the day of the month & year.”

Although Clark named the feature “Pompys Tower” in his original journal entry, Nicholas Biddle altered the name to “Pompey’s Pillar” for the 1814 published history of the expedition. Clark’s inscription is the only known visible evidence of the entire journey that remains intact. Pompeys Pillar was established as a national monument in 2001. An on-site visitor center interprets the expedition’s travels through the Yellowstone River valley.

Lewis & Clark National Historic Trail

Last updated: June 6, 2023