On August 1, 1805, the Lewis and Clark Expedition camped on the south bank of the river opposite the mouth of a creek flowing in from the north. Meriwether Lewis and three others, scouting in hopes of finding Sacajawea’s people, had crossed the mountains to the northeast, come down the North Boulder Valley, and reached this place at 2:00 P.M. They found a herd of elk grazing there, killed two, paused for an elk steak lunch, and then continued upstream, leaving the elk on the riverbank for the expedition’s dinner. Captain Clark and the expedition arrived late that evening after a strenuous day of dragging the boats up canyon rapids with a long rawhide towline that had broken in the rapids below with near calamitous results. Seeing the two elk, the hungry men made camp. Reuben and Jo Fields then hunted up the creek and killed five deer in the willow breaks, leading to the stream being named Field’s Creek, now known as North Boulder. A large brown bear was seen on the south side of the river, Clark shot a bighorn sheep in the canyon, Lewis shot two antelope a short distance upstream, the first Maximilian Jay known to science was seen near camp, and the temperature at sunrise on August 2 was fifty degrees above zero.