American Mountain Men and the Western Fur Trade: Background

Updated: February 4, 2026

American mountain men and the western fur trade helped open the Northern Rocky Mountains to the United States, but they also changed the land and the lives of Native peoples in powerful ways.

What Major Long Got Wrong

Major Stephen H. Long visited the central Great Plains and eastern Rockies in 1819-1820 and called much of the West "almost wholly unfit for cultivation." Today, historians and scientists agree this was incorrect for many places, including what is now Montana, where irrigation, dryland farming, and ranching later supported many communities.

In Long's time, maps of the West were still rough, and ideas about soils, rainfall, and climate were limited. The 1818 agreement between the United States and Great Britain set the border with Canada at the 49th parallel from the Lake of the Woods to the Rockies, but large areas west of the mountains were still claimed by several nations at once.

Whose Land Was It?

Most of what became Montana lay within the 1803 Louisiana Purchase, which the United States bought from France, but western and northwestern Montana remained in a region disputed between the U.S. and Britain until later treaties. The Lewis and Clark Expedition (1804-1806) crossed this area, mapping rivers and mountains and making contact with many Native nations, including the Salish, Nez Perce, and Shoshone.

Long before any American "mountain men" arrived, this land was home to many Native nations such as the Blackfeet (Piegan), Crow, Salish, Kootenai, Assiniboine, and others, each with its own territories and trade networks. These nations controlled access to hunting grounds and river valleys, and traders had to work with them-or sometimes fight them'to survive.

Native Hunting and Buffalo Jumps

Archaeology and oral traditions show that Native people in the Northern Plains used buffalo jumps (pishkuns) for thousands of years before Europeans arrived. Hunters drove bison over cliffs or into steep-walled valleys, then processed the meat, hides, and bones at the base of the jump.

Before horses spread widely into this region in the 1700s, large buffalo hunts required careful planning and teamwork, so bison were heavily used but not wiped out. Many tribes preferred to hunt elk, deer, and bison rather than smaller fur-bearers, because these large animals provided better meat and materials for clothing, tipis, and tools.

Beavers, Beliefs, and Change

In many tribes, beavers and bears had spiritual importance, so people hunted them more selectively. Some groups used simple traps or deadfalls to catch small animals, but, overall, Native communities in this area did not target beavers on a massive scale before the fur trade.

When European and American traders arrived, they encouraged Native people to trap beaver and other fur-bearing animals for trade goods like metal tools, cloth, and guns. This pulled Native families into a new money-based system and sometimes increased pressure on beaver populations in places that had once been lightly trapped.

Why Fur Was So Valuable

In the 1600s-1800s, Europeans wanted warm, comfortable clothing and hats, but cotton and synthetic fabrics were not yet common. Wool cloth could be dyed with indigo (blue) or cochineal (red dye made from insects), but it was often scratchy and expensive.

Beaver fur, especially the soft underfur, could be pressed into strong, water-resistant felt that made excellent hats. Beaver felt hats, especially tall "high hats," became a symbol of wealth and fashion in European cities, which created a huge demand for pelts from North America.

The Global Fur Trade

By the 1600s, French and British traders were competing to control the North American fur trade. The 1763 Treaty of Paris ended most French power in mainland North America and gave Britain a dominant role in many fur regions, though Native nations still controlled most of the land on the ground.

In the late 1700s and early 1800s, big companies formed to organize the trade: the British Hudson's Bay Company and the North West Company, and, later, American firms such as John Jacob Astor's Pacific (American) Fur Company and the Missouri Fur Company. These companies used forts, trade posts, river routes, and Native and mixed-heritage (Métis) workforces to move furs across the continent.

Early Trading Posts in What Became Montana

In 1807, Manuel Lisa, a trader based in St. Louis, helped build a trading post near the mouth of the Bighorn River, close to its junction with the Yellowstone, in what is now southern Montana and northern Wyoming. Posts like Lisa's relied on Native traders, trappers, and interpreters, and they became centers where goods, news, and cultures mixed.

Around the same time, David Thompson of the North West Company built Kootenae (Kootenai) House on the Kootenai River near today's Libby, in northwestern Montana. This post helped link the interior Rockies to fur trade routes that stretched west to the Columbia River and the Pacific Ocean.

Laws, Companies, and Mountain Men

After the War of 1812, the U.S. government wanted American citizens to profit from western furs. In 1816, Congress passed a law that barred foreign companies from trading furs on U.S. soil, although Americans could still hire foreign-born workers.

In 1821 the British North West Company merged into the Hudson's Bay Company, creating one very large firm that dominated much of the northern fur trade. American companies responded by sending "mountain men"-free trappers and company trappers-deep into the Rockies, especially into the rich beaver country of what is now Montana, Wyoming, and Idaho.

Who Were the Mountain Men?

Mountain men were trappers, guides, and explorers who spent much of their lives in the Rocky Mountains during the early 1800s. Some, like Jim Bridger, Jedediah Smith, and John Colter, later helped lead army expeditions, wagon trains, and survey parties.

Many mountain men were of mixed backgrounds: American-born, French Canadian, African American, Native, or Métis, and they often relied on Native families for food, clothing styles, and survival skills. They traveled alone or in small parties, trapping in spring and fall, then meeting at large gatherings called "rendezvous" to trade furs for supplies, swap news, and sometimes celebrate wildly.

Native Peoples as Partners and Rivals

Indigenous nations were not just helpers; they were key trading partners and powerful decision-makers in the fur economy. Many tribes traded beaver pelts and bison robes at forts, then carried trade goods like guns, kettles, and cloth to other groups farther away.

At the same time, conflicts sometimes flared when traders ignored Native interests or trespassed on hunting grounds. On the Upper Missouri, for example, American traders had serious clashes with the Blackfeet and their allies, especially when earlier violent incidents damaged trust.

Environmental and Health Impacts

Modern historians and environmental scientists agree that the fur trade greatly reduced beaver populations in many river systems, and later helped drive down bison numbers as robe trading grew. The Hudson's Bay Company even tried to create "fur deserts" in some areas by trapping beaver so heavily that rival Americans would find no profitable furs left.

The fur trade also brought major health problems. Diseases such as smallpox and measles, carried by newcomers, spread rapidly through Native communities that had no immunity, causing population losses in many parts of the Northwest and along the Columbia River in the 1800s. These losses weakened many tribes just as pressure on land and resources was increasing.

The End of the Beaver Boom

By the late 1830s and 1840s, several changes brought the classic mountain man beaver trade to an end. Beaver numbers had dropped in many easy-to-reach streams, new fashions in Europe favored silk hats instead of beaver felt, and overland travel routes for settlers were starting to replace fur brigades as the main focus of western exploration.

Fur traders shifted to other products such as buffalo robes, timber, and farm goods, while many former mountain men took jobs as scouts, guides, or soldiers, or settled down as ranchers and farmers. The trails and information they helped create, along with the forts and trading posts, made it easier for thousands of newcomers to move into the northern Rockies later in the 1800s.

Rocky Mountain Fur Trade Timeline

Use the buttons to move through the major events of the Rocky Mountain fur trade. This timeline focuses on places and people connected to what is now Montana and the northern Rockies.[web:18][web:51]

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Updated: February 4, 2026