The Oregon Territory had been left out of the 1842
Canadian-American border treaty because both sides, British and
American, were unwilling to flex on the issue. The British claimed the
area south to the Columbia River (today forming most of the border
between the states of Oregon and Washington) whereas the Americans
claimed the area north to the Russian border at Fort Simpson on the
Fraser River or roughly to the 54-40 parallel.
Polk had promised in his presidential
campaign that along with the Texas issue he would bring the Oregon
border conflict with the British to some kind of resolution. Polk thus
proposed a compromise of extending the 49th parallel east of the
Rockies now all the way to the Pacific, though swinging that line a bit
just below Fort Victoria on Vancouver Island facing the strategic Puget
Sound.
At first the British rejected this
proposal. But the Americans made their original claim to the 54-40
parallel something of a war cry ("Fifty-Four Forty or Fight") and the
British decided that the pressing of their own claim was not wise. They
thus instructed British negotiator Packenham to come to terms with
American Secretary of State James Buchanan on the basis of Polk's
original compromise. Terms were quickly agreed on. Thus in mid-June of
1846, just as the Americans were moving against Mexico, the Senate
approved the Oregon Treaty.
The Oregon Trail. Even before the treaty
was signed, both Christian missionaries seeking to bring the Indians to
Christ and land-hungry Americans had begun pouring into Montana, Idaho,
and the Pacific Northwest. Starting their trek from Independence
Missouri, they followed the Missouri and Platte Rivers west to the
Rockies, crossed rivers, mountains, snow, and ice before descending
down into the lush Oregon territory along the Columbia River. By the
time of the 1846 treaty more than 6,000 Americans had made their way to
the Oregon Territory, to begin a new life there.