Pompey’s Pillar National Monument

At the base of the monolithic rock where William Clark (of Lewis and Clark fame) carved his name in 1806 is a small visitor center that illustrates an interesting period when the parties split for a month on their return trip. Displays include replicas of the bullboats some of Clark's men used to float the Yellowstone after their horses were stolen. Find it 30 miles east of Billings.