Lemhi Pass

The road over Lemhi Pass was old long before Lewis found it. When the Agaidika acquired horses in the eighteenth century, this became their way between the parts of their homeland on either side of the divide. Lewis called it a large and plain Indian road.

He came up it on August 12, 1805, with George Drouillard, John Shields and Hugh McNeal, ahead of the main party, looking for the Shoshone and their horses. Two miles below the top, McNeal had stood with a foot on either side of the Missouri's last trickle and thanked God he had lived to bestride it; near the summit Lewis drank from what he called the river's most distant fountain. It was not, and the true source was identified in 1895, some ninety miles away. Then they walked to the top of the divide. Lewis had hoped to look down on a short portage to a river flowing to the Pacific. What he saw instead were immense ranges of high mountains to the west, their tops still carrying snow. Three-quarters of a mile down the western slope he tasted the water of the Columbia for the first time, and the next day he met Cameahwait's people.

At 7,373 feet the pass was the highest point of the expedition's westward route, and from 1803 until 1846 it lay on the western border of the United States. It is a National Historic Landmark, reached by steep, narrow dirt road from Tendoy on the Idaho side or from the Montana side, and at the top a short trail with interpretive signs runs along the divide.