Pompeys Pillar
Montana
On July twenty-fifth, eighteen oh six, Captain William Clark climbed this sandstone butte rising one hundred fifty feet above the Yellowstone River and carved his name and the date into the rock face. It is the only physical evidence of the Lewis and Clark Expedition that survives in the landscape. Clark called it Pompy's Tower, after his nickname for Sacagawea's toddler son Jean Baptiste Charbonneau, who had traveled with the Corps of Discovery as an infant.
The name was changed to Pompeys Pillar in eighteen fourteen, when the account of the expedition was published. The signature is now protected so visitors can see it without touching it. President Clinton designated the site a national monument in two thousand and one.
