The expedition towed their canoes up the Beaverhead River, one of the small winding tributaries of the Jefferson River, toward the Continental Divide. They were badly in need of horses and anxious to meet the Shoshones, who might trade with them. The Beaverhead flows from left to right, through the small town of Twin Bridges, into the center of the photo. The stream with the brighter sand banks is the Big Hole River, which at first Clark incorrectly thought was the branch to take.

When Sacagawea saw this landmark, Beaverhead Rock, she knew that her tribe's summer camp was close by, and the Captains were much relieved.

After small hunting parties had encountered Shoshone braves who fled from the strangers, Lewis finally came upon an elderly woman and two girls who agreed to take him to their village. When the leaders were later brought to Lewis' camp, Sacagawea found that her own brother, Cameahwait, was Chief. A good relationship was forged and the Corps was later able to secure the horses and supplies they needed. The site of this critical part of the journey was called Camp Fortunate, but it is now under Clark Canyon Reservoir, shown here.

After caching the canoes at Camp Fortunate, the Corps traveled on foot with horses carrying their supplies. They followed Horse Prairie Creek, a small and meandering stream, westward toward Lemhi Pass.

At Lemhi Pass the expedition crossed the Continental Divide at an elevation of 7373 feet. Although the explorers had hoped to find a moderate descent leading to plains of the Columbia River, Lewis saw "immence ranges of high mountains still to the West of us with their tops partially covered with snow."

On the beautiful and calm day we had for our crossing, the Citabria is able to explore the higher reaches of the ranges near Lemhi Pass.

The Continental Divide is truly the backbone of the Rockies. The highest peaks just north of Lemhi Pass are at about 11,000 feet.