A Highway to the Pacific: Thomas Jefferson and the Far West
It seems Thomas Jefferson imagined that initially only fur traders and Indians would inhabit the lands west of the Mississippi. He acknowledged, however, that once the lands on the eastern side of the great river were filled up, the independent farmers of his agrarian ideal would need more space. Jefferson read widely about Louisiana and the hinterland and was responsible for organizing the first explorations into the trans-Mississippi region. After he became President in 1801, he sent Meriwether Lewis and William Clark on an ostensibly scientific mission over the Rocky Mountains and all the way to the mouth of the Columbia River at the Pacific Ocean. The expedition aimed as well to discover a route which would allow American fur traders to challenge the aggressive British traders' uncontested control of the upper Missouri.
The resulting route over the Rockies and down to the Columbia involved far too much land carriage--about 340 miles--to be of use to traders. American struggles against the domination of British imperial trade were largely unsuccessful, but Lewis and Clark's expedition had proved that the continent was traversable, a fact that continued to burn in the American imagination. The discovery of what would become known as the Oregon Trail had provided frontier farmers with the option of moving west, and in the economic distresses of the 1830s and 40s many did. The eventual withdrawal of the Hudson Bay Company from the Oregon territory and the subsequent signing of the Treaty of 1846--which established the present border of the U. S. at the 49th parallel--only made official what had happened much earlier: the American agricultural frontier had reached the Pacific.