United States
45.9990°, -108.0010°
2001
2.1
Pompeys Pillar National Monument preserves a 150-foot tall sandstone butte along the Yellowstone River that bears the only remaining physical evidence of the Lewis and Clark Expedition. The monument is managed by the Bureau of Land Management and features Captain William Clark's signature carved into the rock on July 25, 1806. The pillar has served as a landmark for travelers for thousands of years, from Native American tribes to fur traders and pioneers. The site includes interpretive trails and exhibits about the area's natural and cultural history.