On August 8, 1805, working the canoes up the river that now carries the hill's name, the expedition came in sight of a long bluff above the Beaverhead. Sacagawea, an Agaidika Shoshone woman captured as a girl by Hidatsa raiders at the Three Forks, recognized it. Meriwether Lewis wrote that her people called the hill the beaver's head for its shape, and that she told them their summer retreat lay on a river beyond the mountains to the west, not far off. It was the news the captains had been waiting on: the Shoshone had horses, and without horses there was no getting over the mountains.
Lewis set out overland the next morning with three men and found the Shoshone across Lemhi Pass on August 13. Clark brought the canoes past the rock on August 10, and the compass bearings he took a few days later fix this bluff as the one she meant. That matters, because the name wandered. Local usage long called this outcrop Point of Rocks and gave the name Beaverhead to the Rattlesnake Cliffs, about twenty-five miles southwest, which, as a National Park Service survey conceded, look more like a beaver's head than this does. From the highway, at speed, the likeness is hard to find either way.
The rock is a state park with no facilities. The usual view is from the pullout on MT-41, about fourteen miles south of Twin Bridges, which has interpretive signs; a rough road reaches the rock itself and is not maintained in winter. It can also be seen from Clark's Lookout State Park in Dillon.
The closest stops worth working into your route