The spirit of "Manifest Destiny" pervaded the United States during the Age of Reform—the decades prior to the Civil War. John L. O'Sullivan, editor of the influential United States Magazine and Democratic Review, gave the expansionist movement its name in 1845, when he wrote that it is "the fulfillment of our manifest destiny to overspread the continent allotted by Providence for the free development of our yearly multiplying millions." Manifest Destiny was stimulated by nationalism and an idealistic vision of human perfectibility. It was America's duty to extend liberty and democratic institutions across the continent. Underlying this divine American mission was a feeling of cultural—even racial—superiority. Anglo-Saxon Americans believed that they had a natural right to move west, bringing with them the blessings of self-government and Protestantism. Americans gradually had been moving westward for two centuries, but in the 1830s and 1840s they pushed across the continent.

By the early nineteenth century, Spain, Russia, Great Britain, and the United States claimed sovereignty to the Oregon country. Oregon was a sprawling region of half a million square miles west of the Rocky Mountains to the Pacific, between what is now the northern boundary of California and the southern tip of Alaska. Spain ceded its claims with the Transcontinental Treaty, negotiated in 1819 by John Quincy Adams, by which the United States acquired Florida and relinquished any nebulous claims to Texas under the Louisiana Purchase. In the mid-1820s, Russia acknowledged that Alaska extended only to the present-day southern boundary of 54o 40' north latitude, and ultimately sold its holdings north of San Francisco at Fort Ross to settlers.

The withdrawal of Spain and Russia left Oregon to the United States and Great Britain. Both had strong claims to the region based on discovery and occupation. George Vancouver, a British naval officer following up on the voyages of Captain James Cook, explored the coastline in 1792, and the Hudson Bay Company subsequently established fur-trading posts. Also in 1792, Robert Gray, an American fur merchant sailing out of Boston aboard the Columbia, discovered the majestic river named for his ship. Lewis and Clark wintered on the Oregon coast during their famous expedition, and John Jacob Astor's Pacific Fur Company built Astoria in 1811.

The United States and Britain agreed to the "joint occupation" of Oregon in 1818, when Spain and Russia still had claims to the region, allowing the citizens of each nation equal access to the territory. Merchant mariners and "mountain men" who worked for the various fur companies shared Oregon with the Indians, but there were few white settlers. Then, in 1829, Hall J. Kelley renewed interest in the region with the American Society for Encouraging the Settlement of the Oregon Country.

The Reverend Jason Lee, and several other Protestant missionaries sent to convert the Flathead Indians, settled in the Willamette River valley, south of the Columbia, by the 1830s. Dr. Marcus Whitman and his wife Narcissa, who was among the first group of white women to cross the Rockies, built their mission east of the Cascade Mountains among the Cayuse Indians. The Whitmans, who never learned to appreciate the natives’ culture or social customs, were killed by the Cayuses after a measles epidemic decimated the tribe. Other missionaries also faced resistance from the Indians who wished to maintain their traditional ways, and began encouraging white emigration to extend "civilization" to the territory. There were about 500 Americans living in the region by the end of the decade, sending back reports on the temperate climate, abundant forests, and fertile soil.

Motivated by the spirit of Manifest Destiny, "Oregon Fever" seized thousands of western Americans hard hit by the economic depression—known as the Panic of 1837—triggered largely by an over-speculation in federal lands. Independence, Missouri, was the starting point of the 2,000 mile Overland Trail, blazed by Jedediah Smith, Jim Bridger, and other mountain men. Commonly referred to as the "Oregon Trail," the route ran along the Missouri and Platte Rivers, across the Great Plains, and through the South Pass of the Rocky Mountains. West of the continental divide, in present-day Idaho, wagon trains either moved into Oregon down the Snake and Columbia Rivers or turned southward along the California Trail.

In the years prior to the Civil War, more than 300,000 Americans traveled west, typically with all their belongings in "prairie schooners," canvas-covered wagons typically pulled by oxen. Most of the Oregon pioneers were young farm families from the middle west, who completed the difficult journey in five or six months. A high percentage of the California gold-seekers were young, unmarried men, who expected to return to their families as wealthy men. Many overland pioneers died on the trail—17 per mile, according to one estimate—but fewer than 400 were killed by hostile Indians. The various Indian tribes frequently developed a flourishing trade with the whites passing through their lands, and occasionally served as scouts for the wagon trains.

It was clear that the joint occupation of Oregon could not continue indefinitely. About 5,000 Americans had made the trek to Oregon by the mid-1840s, most of them settling south of the Columbia River. There were perhaps 700 British citizens living near Fort Vancouver on the north bank of the Columbia. Daniel Webster and Lord Ashburton discussed the Oregon issue during their negotiations in 1842, but did not reach an agreement. President John Tyler suggested that the boundary line be extended from the Rocky Mountains along the forty-ninth parallel, but the British refused to relinquish their claims to the Columbia. The spirit of Manifest Destiny could not be held in check for long, however, and the presidential election of 1844 ultimately determined the extent of American territorial expansion.

Copyright 2006 The Regents of the University of California and Monterey Institute for Technology and Education