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Lemhi Pass

Straddling the border of Idaho and Montana, Lemhi Pass sits just over 7,000 feet above sea level. It is a crucial crossing of the Continental Divide, a natural barrier that historically separated watersheds and civilizations, playing a significant role in the shaping of the American West, but today stands as a National Historic Landmark.

Before the arrival of Lewis and Clark, the Lemhi Pass area had been a key route for Native American tribes for centuries, including the Lemhi Shoshone, who lived in the region long before European settlers arrived. The Shoshone would travel around the rugged terrain of the Lemhi Valley on horseback by the 1700s, using the valley’s rivers including the Salmon River, as critical resources and the pass’s strategic location as an important crossing point through the Rockies.

Lemhi Pass first came into the American spotlight in 1803 at the time of the Louisiana Purchase when it sat on the new nation’s western boundary, but became more significant in 1805 during Lewis and Clark’s expedition. On August 12, 1805, Captain Meriwether Lewis and three others scouted 30 miles ahead of the rest of their group and crested the pass from the Montana side, becoming the first known Americans to cross the Continental Divide. In his journal, Lewis described the landscape as “immense ranges of high mountains” covered with snow. Although they had hoped to find a more forgiving route westward toward the Columbia River, they were fascinated by the ranges and excited about entering lands just beyond the American frontier into present-day Idaho.

The crossing of Lemhi Pass was a key milestone in the expedition’s journey. Lewis and his men continued westward and drank from Horseshoe Bend Creek, which they believed to be the waters of the Columbia River and marked the division between the Missouri and Columbia River basins. According to interpretations of the expeditions’ accounts, Captains Lewis and Clark would cross Lemhi Pass a total of five times in August of 1805, including crossings with Sacagawea and Toussaint Charbonneau. Within those crossings, Sacagawea was reunited with her brother, Cameahwait, a Shoshone chief who lived in the Lemhi Valley of Idaho and provided the expedition with horses.

In the 1820s, fur traders began to use Lemhi Pass, which led to a few skirmishes with Native Americans. The fur trade in the early 19th century was driven by European demand for beaver pelts for clothing and accessories, which led to the near extinction of beaver populations in areas of present-day Idaho. The British Crown ordered the Hudson’s Bay Company, to send brigades of fur trappers to “exhaust the animal populations” and use natural boundaries like the Rocky Mountains as buffers to prevent settlement in these newly opened lands. By the 1830s, the demand for furs, particularly beaver, waned in favor of silk, and the Hudson’s Bay Company established a monopoly on trade by building forts through Idaho and Shoshone territory. Hudson’s Bay Company officials wanted to use Lemhi Pass as the point of origin on the continental divide for an Oregon country boundary between Britain and the United States, but this arrangement never came to fruition.

In the mid-19th century, as American expansionism grew, the area around Lemhi Pass became a focal point for settlers. In 1855, the Mormon community, under Brigham Young, established Fort Limhi near the pass, hoping to convert the Lemhi Shoshone to Christianity. The fort was named after King Limhi, a figure in the Book of Mormon, and represented a significant Mormon effort to expand westward. However, conflicts with local tribes and a challenging environment led to the fort’s abandonment after three years, but the name “Lemhi” stuck and eventually came to encompass the surrounding valley, river, and mountain range.

The region surrounding Lemhi Pass continued to evolve as the discovery of gold in the Lemhi Mountains in the 1860s brought prospectors to the area and spurred the need for more settlements like Salmon. As mining operations expanded, so did the need for better transportation routes. Initially, old Native American trails through the pass were widened into roads for freight wagons, and in the late 1870s, a narrow-gauge railroad was built to transport freight and passengers to and from mining camps across Lemhi Pass. In 1884, a stagecoach service connected the Lemhi Valley to nearby mining towns and settlements like Tendoy, Leadore, and Salmon. However, the railroad soon became the dominant mode of transport and in 1910, the Gilmore and Pittsburgh Railroad replaced the stagecoach line, offering a direct route to those towns to haul ore. The railroad was primarily built to transport ore from Leadore’s mines to the Union Pacific junction at Armstead, but by the late 1920s, the mines were exhausted—and with the rise of automobiles and trucks, the railroad faded into obscurity. By the mid-20th century, much of the regional traffic shifted to Highway 93 and U.S. 91 (now Interstate 15). Although the days of high traffic are long gone for Lemhi Pass, the area has gained some renewed attention due to its potential for rare earth mineral deposits, which are essential for the production of semiconductors—a strategic resource for the future of technology and national security.

Today, Lemhi Pass is a dirt road in a remote and largely untouched area, still tucked away in the Beaverhead Range on the border of Idaho and Montana. Nearby Leadore, with a population of just 90, is a historic ghost town, while Tendoy, home to nearly 200 people, is a quiet farm and ranch community. Lemhi Pass was designated a National Historic Landmark in 1960 and currently receives most of its traffic from U.S. Forest Service employees and ranchers, with the occasional modern-day explorers and history buffs retracing the route once followed by Lewis, Clark, and Sacagawea. From the summit, one can see and read historical markers and take in the same views shared by Native Americans, explorers, miners, settlers, and travelers across time—expansive, wild landscapes stretching in every direction, with peaks of the Bitterroot and Salmon River Ranges outlining the sky.

 

Written by Noé Zepeda

 

Sources

https://history.idaho.gov/wp-content/uploads/2018/09/fortlemhi.pdf

Across the Great Divide

https://www.visitmt.com/listings/general/national-historic-site/lemhi-pass

https://clui.org/ludb/site/lemhi-pass

https://www.nps.gov/parkhistory/online_books/lewisandclark/site3.htm

https://postalmuseum.si.edu/exhibition/indians-at-the-post-office-murals-trade-and-commerce/th

e-fur-traders

https://www.realclearenergy.org/articles/2023/02/21/future_semiconductor_legislation_needs_to_support_critical_mineral_projects_883074.html

Fort Limhi: The Mormon Adventure in Oregon Territory, 1855-1858 David L. Bigler Arthur H. Clark Company, 2003 – Biography & Autobiography – 372 pages

https://history.idaho.gov/wp-content/uploads/0486_Lemhi-in-Early-Nineteenth-Century.pdf

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