Oregon Country was the huge area between the Pacific Ocean and the Rocky Mountains north of California. It included all of what is now Oregon, Washington, and Idaho, plus parts of Montana and Wyoming. The region also contained about half of what is now the Canadian province of British Columbia. In the early 1800s, four nations laid claim to the vast, rugged land. The United States based its claim on Robert Gray’s discovery of the Columbia River in 1792 and on the Lewis and Clark expedition. Great Britain based its claim on British explorations of the Columbia River. Spain, which had also explored the Pacific coast in the late 1700s, controlled California to the south. Lastly, Russia had settlements that stretched south from Alaska into Oregon.

Many Americans wanted control of the Oregon to gain access to the Pacific Ocean. Secretary of State John Quincy Adams played a key role in promoting this goal. In 1819, he negotiated the Adams-Onís Treaty with Spain. In the treaty, the Spanish agreed to set the limits of their territory at what is now California’s northern border and gave up any claim to Oregon. In 1824, Russia also surrendered its claim to the land south of Alaska. Only Britain remained to challenge American control of Oregon. In 1818, Adams had worked out an agreement with Britain for joint occupation of the area. This meant that people from both the United States and Great Britain could settle there. When Adams became president in 1825, he proposed that the two nations divide Oregon along the 49°N line of latitude. Britain refused, insisting on a larger share of the territory. Unable to resolve their dispute, the two countries agreed to extend the joint occupation. In the following years, thousands of Americans streamed into Oregon, and they pushed the issue toward resolution.

The first Americans to reach Oregon were not farmers but fur traders. They had come to trap beaver, whose skins were in great demand in the eastern United States and in Europe. The British established several trading posts in the region, as did New York merchant John Jacob Astor. In 1808, Astor organized the American Fur Company, which soon became the most powerful of the fur companies in America. It allowed him to build up trade with the East Coast, the Pacific Northwest, and China.

At first, the merchants traded for furs that the Native Americans supplied. Gradually, American adventurers joined the trade. These people, who spent most of their time in the Rocky Mountains, came to be known as mountain men. The tough, independent mountain men made their living by trapping beaver. Many had Native American wives and adopted Native American ways. They lived in buffalo-skin lodges and dressed in fringed buckskin pants, moccasins, and beads. Some mountain men worked for fur-trading companies; others sold their furs to the highest bidder. Throughout the spring and early summer, they ranged across the mountains, setting traps and then collecting the beaver pelts.

As they roamed searching for beaver, the mountain men explored the mountains, valleys, and trails of the West. Jim Beckwourth, an African American from Virginia, explored Wyoming’s Green River. Robert Stuart and Jedediah Smith both found the South Pass, a broad break through the Rockies. South Pass later became the main route that settlers took to Oregon. To survive in the wilderness, a mountain man had to be skillful and resourceful.

In time, the mountain men killed off most of the beaver and could no longer trap. Some went to settle on farms in Oregon. With their knowledge of the western lands, though, some mountain men found new work. Jim Bridger, Kit Carson, and others acted as guides to lead the parties of settlers now streaming west.

Americans began traveling to the Oregon Country to settle in the 1830s. Reports of the fertile land persuaded many to make the journey. Economic troubles at home made new opportunities in the West look attractive. Among the first settlers of the Oregon Country were missionaries who wanted to bring Christianity to the Native Americans. Dr. Marcus Whitman and his wife, Narcissa, went to Oregon in 1836 and built a mission among the Cayuse people near the present site of Walla Walla, Washington. New settlers unknowingly brought measles to the mission. An epidemic killed many of the Native American children. Blaming the Whitmans for the sickness, the Cayuse attacked the mission in November 1847 and killed them and 11 others. Despite this, the flood of settlers continued into Oregon.

In the early 1840s, “Oregon fever” swept through the Mississippi Valley. The depression caused by the Panic of 1837 had hit the region hard. People formed societies to gather information about Oregon and to plan to make the long trip. The “great migration” had begun. Tens of thousands of people made the trip. These pioneers were called emigrants because they left the United States to go to Oregon. Before the difficult 2,000-mile journey, these pioneers stuffed their canvas-covered Conestoga wagons, called prairie schooners, with supplies. From a distance these wagons looked like schooners (ships) at sea.

Gathering in Independence or other towns in Missouri, they followed the Oregon Trail across the Great Plains, along the Platte River, and through the South Pass of the Rocky Mountains. On the other side, they took the trail north and west along the Snake and Columbia Rivers into the Oregon Country. Most American pioneers headed for the fertile Willamette Valley south of the Columbia River. Between 1840 and 1845, the number of American settlers in the area increased from 500 to 5,000, while the British population remained at about 700. The question of ownership of Oregon arose again.

The settlers in Oregon insisted that the United States should have sole ownership of the area. More and more Americans agreed. As a result, Oregon became a significant issue in the 1844 presidential election. James K. Polk received the Democratic Party’s nomination for president, partly because he supported American claims for sole ownership of Oregon. Democrats campaigned using the slogan “Fifty-four Forty or Fight.” The slogan referred to the line of latitude that Democrats believed should be the nation’s northern border in Oregon, which would have placed the border far north, within the modern Canadian province of British Columbia.

Henry Clay of the Whig Party, Polk’s principal opponent, did not take a strong position on the Oregon issue. Polk won the election because the antislavery Liberty Party took so many votes from Clay in New York that Polk won the state. Polk won 170 electoral votes to 105 for Clay. Filled with the spirit of Manifest Destiny, Polk was determined to make Oregon part of the United States. Britain would not accept a border at “Fifty-four Forty,” however. To do so would have meant giving up its claim entirely. Instead, in June 1846, the two countries compromised, setting the boundary between the American and British portions of Oregon at 49°N latitude.