At the very beginning of the 19th century, almost no one knew what lay beyond the Mississippi River. Fragmentary reports from fur traders told of vast prairies and high mountain ranges, but the geography between St. Louis, Missouri and the Pacific Ocean essentially remained a vast mystery.
A series of exploratory journeys, beginning with Lewis and Clark, began to document the landscape of the West.
And as reports eventually circulated of winding rivers, towering peaks, vast prairies, and potential riches, the desire to move westward spread. And Manifest Destiny would become a national obsession.
The best known, and first, great expedition to the West was conducted by Meriwether Lewis, William Clark, and the Corps of Discovery from 1804 to 1806.
Lewis and Clark ventured from St. Louis, Missouri to the Pacific Coast and back. Their expedition, the idea of President Thomas Jefferson, was ostensibly to mark out territories to help the American fur trade. But the Lewis and Clark Expedition established that the continent could be crossed, thus inspiring others to explore the vast unknown territories between the Mississippi and the Pacific Ocean.
A young U.S. Army officer, Zebulon Pike, led two expeditions into the West in the early 1800s, first venturing into present day Minnesota, and then heading westward toward present day Colorado.
Pike's second expedition is puzzling to this day, as it's unclear whether he was simply exploring or actively spying on Mexican forces in what is now the American Southwest. Pike was actually arrested by the Mexicans, held for a time, and eventually released.
Years after his expedition, Pike's Peak in Colorado was named for Zebulon Pike.
In the first decade of the 19th century the richest man in America, John Jacob Astor, decided to expand his fur trading business all the way to the West Coast of North America.
Astor's plan was ambitious, and entailed founding a trading post in present day Oregon.
A settlement, Fort Astoria, was established, but the War of 1812 derailed Astor's plans. Fort Astoria fell into British hands, and though it eventually became part of American territory again, it was a business failure.
Astor's plan had one unexpected benefit when men walking eastward from the outpost, taking letters to Astor's headquarters in New York, discovered what would later be known as the Oregon Trail.
Robert Stuart: Blazing the Oregon Trail
Perhaps the greatest contribution of John Jacob Astor's western settlement was the discovery of what later became known as the Oregon Trail.
Men from the outpost, led by Robert Stuart, headed eastward from present day Oregon in the summer of 1812, carrying letters for Astor in New York City. They reached St. Louis the following year, and Stuart then continued onward to New York.
Stuart and his party had discovered the most practical trail to cross the great expanse of the West. However, the trail did not become widely known for decades, and it wasn't until the 1840s that anyone beyond a small community of fur traders began to use it.
John C. Frémont's Expeditions in the West
A series of U.S. government expeditions led by John C. Frémont between 1842 and 1854 mapped extensive areas of the West, and led to increased westward migration.
Frémont was a politically connected and controversial character who picked up the nickname "The Pathfinder" though he generally traveled trails that were already established.
Perhaps his greatest contribution to westward expansion was a published report based on his first two expeditions in the West. The U.S. Senate issued Frémont's report, which contained invaluable maps, as a book. And a commercial publisher took much of the information in it and published it as a handy guidebook for emigrants wishing to make the long overland trek to Oregon and California.