Lemhi Pass - History

History

The pass gained importance in the 18th century, when the Lemhi Shoshone acquired horses and used the route to travel between the two main parts of their homeland. From the time of the Louisiana Purchase in 1803 until the Oregon Treaty in 1846 the pass marked the western border of the United States. On August 12, 1805 Meriwether Lewis and three other members of the Lewis and Clark Expedition crossed the Continental Divide at Lemhi Pass. Lewis found a "large and plain Indian road" over the pass. This was the first time that white men had seen present-day Idaho:

We proceeded to the top of the dividing ridge from which I discovered immense ranges of high mountains still to the West of us wth their tops partially covered in snow

The next day Lewis met Cameahwait and his band of Shoshone, and returned with them across the pass to meet Clark. On August 26, 1805 the entire expedition crossed the pass.

In the early 19th century the pass was regularly used by the Blackfoot people, so that in 1824 Alexander Ross referred to the route as the Blackfoot route. At that time the pass itself was known as North Pass, to distinguish from South Pass. The pass derives its present name from Fort Lemhi, founded in 1855 by Mormon missionaries who were the first non-Indians to establish a sustained relationship with the Salmon River Indian people.

During the mining era the pass was used by stagecoaches, but the route fell into disuse after 1910, when the Gilmore and Pittsburgh Railroad was built through the nearby Bannock Pass. Only a single track dirt road now crosses the pass.

The pass was designated a National Historic Landmark in 1960.