On July 25, 1806, three weeks after the Lewis and Clark Expedition split up to explore different river valleys, Capt. William Clark’s group camped at the base of the only rock outcropping for miles in either direction on the south side of the Yellowstone River. Clark climbed the 150-foot-high mesa to scan the horizon, and on his way back inscribed his first initial, last name and date in the vulnerable sandstone.
Clark called the landmark “Pompy’s Tower” for the son of Sacagawea, the Shoshone Indian woman who rescued the expedition two winters earlier. Time has been gentle to the only visible legacy of the expedition, even if people have not. Dozens of other names have been etched into the stone near Clark’s, and stewards of the pillar long ago were forced to put the inscription under lock and glass. Yet you can’t help but feel a sense of awe while gazing at a 210-year-old etching.
Pompeys Pillar became a national monument in 2001 and an interpretive center was built in 2006. Interpretive signs with quotes from Clark’s journal line trails. Paths also meander among 100-year-old cottonwoods along the river. During the offseason, visitors may park at the gate and make the one-mile walk to the pillar.