Pompeys Pillar is on the banks of the Yellowstone River. The town is named for the nearby rock outcropping, which is today Pompeys Pillar National Monument. The sandstone pillar rises 200 feet above the Yellowstone River 30 miles east of Billings. Pompeys Pillar is like a history book that reads like a who's who of western frontier history. The rock face bears the remains of animal drawings created by people who used the area for rendezvous, campsites, and hunting. In 1806 Captain William Clark carved his signature and the date in this rock. It is the only site on the trail where visible evidence of the Lewis and Clark Expedition may be viewed by the public.During his return trip to St. Louis, William Clark of the Lewis and Clark Expedition climbed the Pillar and carved his signature and the date in the sandstone. Clark wrote, "This rock I ascended and from it's top had a most extensive view in every direction on the Northerly Side of the river high romantic Clifts approach and jut over the water for Some distance both above and below...I marked my name and the day of the month and year."While archeological digs and other recent research have uncovered artifacts that may have been left by the Corps of Discovery, Clark's inscription is still the only remaining physical evidence of Lewis and Clark's passing visible on their actual route. This historic carving on the sandstone butte that Clark called a "remarkable rock" has inspired generations of visitors for more than 100 years.In his journals, Clark named the Pillar "Pomp's Tower." Pomp was Clark's nickname for young Baptiste Charbonneau, infant son of Sacagawea, the Shoshoni woman who accompanied the expedition and contributed greatly to its success. An image of Sacagawea carrying young Pompy adorns the United States golden dollar coin. Pompy means little chief in the Shoshoni language. The name was changed to Pompeys Pillar when an account of the Expedition was published by Nicolas Biddle in 1814.