Pompey's Pillar National Monument

Pompey's Pillar National Monument spans 51 acres along the Yellowstone River, featuring a massive 2-acre sandstone outcrop that rises 120 feet high. This celebrated landmark and observation point, situated at a natural ford in the Yellowstone River, is distinctive due to its geology and bears hundreds of markings, petroglyphs, and inscriptions left by visitors, including William Clark of the Lewis and Clark Expedition.