The Oregon Trail: A Migratory Route of

Manifest Destiny

Michael Ahn

            When Thomas Jefferson instructed Merriweather Lewis and William Clark

to explore the Missouri river, and such principal stream of it, as, by it's course & communication with the waters of the Pacific Ocean, whether the Columbia, Oregon, Colorado and/or other river may offer the most direct and practicable water communication across this continent, for the purposes of commerce,”

these words sparked a generation of westward expansion in the young, growing nation of the United States of America.  As the Lewis and Clark Company completed the first ever transcontinental expedition to the Pacific coast by Americans, the trail blazed by these explorers would evolve to become the most important and largest migration route in the history of the American west: a network of trails, paths, rivers and ferries known as the Oregon Trail.  By looking at the history and development of the Oregon Trail, the effects and adaptations of human interaction with the new frontier are inextricably tied to major population changes and technological advances occurring in the middle of the 19th century. 

What is now known as the Oregon Trail never established itself from the beginning; it developed over a series of expeditions led by British and American explorers, fur trappers, traders and postal workers.  Between 1804 and 1806, Lewis and Clarke traversed the Rocky Mountains and followed the Missouri, Columbia, and Snake Rivers that meandered throughout Oregon Country until they reached the Pacific Coast.  This expedition was valuable in its mapping of the geography of the newly acquired territory (from the Treaty of Ghent ending the War of 1812), establishing relations with Native Americans and determining possible routes for wagons through the difficult mountain ranges.  It had been Jefferson’s intention to explore these lands and eventually use the resources to stimulate the economy, wealth and population of the United States.  However, as the majority of the growing population were already content with settling in newly formed states within the Louisiana Purchase and unwilling to make the 2,000 mile, 4 month journey, the first initial benefactors inhabiting Oregon Country were trading posts scattered along commonly used trails.  Up until the 1840’s, trading posts such as Fort Hall, Fort Boise and Fort Walla Walla in Oregon served as hubs for fur trappers and traders, usually shipping beaver fur to the American, Canadian and British fashion and clothing economy.  Originally managed by the Hudson’s Bay Company, these trading posts would later serve as life-saving checkpoints to restock supplies, repair wagons and tend to the ill for the thousands of passing wagon parties.  Between 1810 and 1840 about 3,000 trappers, traders, explorers and mountain men, typically employed by British and American fur companies, were traveling and roaming the wild forests and ranging plains living a life akin to indigenous and nomadic cultures with minimal damage to the environment. 

Map of the Oregon Trail


After the 1840’s and the demand for fur dramatically fell, the many and plentiful resources of the Northwest was the calling for numerous migrations of pioneers and settlers.  The Great Migration of 1843 was the first major movement of civilians entering Oregon Country and they eventually settled in the Willamette Valley, home of Portland, Salem and Eugene and nearly 70% of modern day Oregon’s population.  The estimated 1,000 emigrants further improved and solidified a route connecting the Pacific Coast with the Midwest by clearing forest blockades and carving passes in mountainous ranges. 

The bridge towards unclaimed and lawless land (the American law did not fully extend beyond the Continental Divide) also presented itself as an opportunity for emerging cultural movements, for example the Mormons and the Church of Latter Day Saints.  Facing prosecution and mob threats from Protestant communities in the Midwest, in 1847 the Church of Latter Day Saints migrated along the Oregon Trail to establish a large settlement in Salt Lake City, Utah under the leadership of Brigham Young.  Between 1847 and 1860, over 43,000 Mormon pioneers would traverse the Oregon and California Trail, forming and expanding settlements into towns and cities.  The American West seemed to harbor an endless supply of opportunities and riches available to those willing to venture far enough and able to tame the wild virgin wilderness.

In 1848, another opportunity shined in the eager eyes of hopeful men: California gold.  When James Marshall first discovered a gold nugget in the American River and sparked the California Gold Rush the huge influx of men from all over the country into the California wilderness unearthed an enormous wealth of gold (estimated $50,000,000 worth of gold per year), bolstering the economy and development of San Francisco and many mining towns.  The Oregon Trail again saw a huge spike in traffic with increased forest clearings, shortcuts and branching trails. 

However, the end of the Gold Rush also witnessed dwindling wagon parties arriving via land trails; instead the advancement of faster, safer, easier and more efficient modes of transportation essentially faded out the Oregon Trail in carrying the thousands of settlers and emigrants to the Pacific.  In 1855, the Panama Canal Railway was completed, linking the Pacific and Atlantic Ocean over a 47.6-mile isthmus and easily transporting passengers shipping from New Orleans, Louisiana to ports in California and Oregon.  With the improving technology of steamboats, this link proved to be a great time-saver for those traveling by water, instead of having to circumvent South America.  In 1869, the First Transcontinental Railroad was completed and provided the fastest, safest and cheapest way to travel between coasts, thrusting the final coup de grace in retiring the Oregon Trail.   

Nevertheless, the Oregon Trail laid down the essential frames for the development of many influential technologies, which bolstered the infrastructure and economy and further connected people across great distances.  The stagecoach industry, Postal Service and Pony Express company all used major portions of the trail to deliver their goods and mails throughout the emerging towns, establishing stations and stops for their employees.  Telegraph lines, most of which initially followed the much of the Oregon Trail before switching to parallel the railroad tracks, would eventually replace the Pony Express service.  The trails also allowed for massive herding and driving of cattle, horses, sheep, goats and fowl from the Midwest and essentially introduced domestic animals into the ecosystem and economy of the West.  And despite the very low traffic atop the Oregon Trail itself, many modern day highways and railroads still follow alongside the same trails utilized by pioneers and settlers.        

But the Oregon Trail, as monumental and helpful as it was for the American people, was without its fair share of environmental damages.  At the very least, the trails needed to be cleared of obstacles such as trees and cliffs and so timber was cut and mountains were carved to allow ample passage for wagons and animals.  Upon arrival at the destinations, the growing population of settlers, farmers and families further cleared and shaped the land to fit their societal and agricultural needs, tilling vast crop fields, irrigating canals from rivers, and exploiting the rich resources for human commerce.  Today, the California Central Valley has become a huge expanse of crop fields and grows a majority of the produce distributed in the nation.  The Gold Rush was also responsible for the incredible amount of damages, mostly in the rivers, cliffs and mountains, caused by mining, digging, and erosion.  But thanks to conservation efforts by figures such as John Muir and Theodore Roosevelt, much of the original wilderness in the Sierra Mountain Ranges and Yosemite Valley remain protected from further environmental harm. 

The presence of a channel cutting through the heart of uncharted North American lands also caused disturbances and conflicts with the native population.  Between 1834 and 1869, the population of the West rose by 400,000 Americans from neighboring states, and with the increasing presence of American societies and culture, the Native American population was quickly completely displaced from their own lands.  Tribes lost all control of their sacred lands; lands passed down from their ancestors that were sources for hunting (the millions of roaming bison would eventually become endangered), rituals, burials, culture, religion and history.  Despite valiant efforts among resistant tribes to keep white men at bay, the swelling tidal wave of Americans bent on Manifest Destiny would crush these spirits as they claimed and ate from their enemies’ lands.  This would also occur to a smaller extent to the Mexican inhabits of the Southwest (Texas, Arizona, New Mexico) and California before the United States government acquired these territories.  By the end of 1870, census showed that nearly 900,000 Americans inhabited the western states, 560,000 of which resided in California.

Depending on which perspective is used, the Oregon Trail could be seen as an instrument of migration, invasion, exploitation or destruction.  What started out as an expedition to the Pacific evolved to become a major artery connecting the Pacific with the Midwest.  From this artery, smaller branches and vessels would feed outwards and expand its reaches to all rich and bountiful locales.  Looking at the footsteps left by the companies, parties and migrations illustrates the history and cultural evolutions taking place in 19th Century America, a culture and lifestyle very dear to the identity of the many ratified Western states thanks to the Oregon Trail. 


Jackson, Donald, ed. Letters of the Lewis and Clark Expedition with Related Documents. Second Edition. Urbana: University of Illinois Press, 1978

G. B. Dobson, January 6, 2004. Wyoming Tales and Trails. 1999-2010

Lindeblad, Beng,  American West: A Celebration of the Human Spirit, 2008

Unruh, John D. The Plains Across the Overland Emigrants and Trans-Mississippi West 1840–1860. University of Illinois Press.   1993

Return to ENVS2 homepage

Send message to Swarthmore College Environmental Studies

last updated 3/31/10