The Oregon Country was jointly occupied by the U.S. and Great Britain from 1818, when the two countries signed a treaty formalizing relations after the War of 1812, until 1846, when they divided the Oregon Country along the 49th parallel. In the course of producing these maps, the museum's curator, Ken Favrholdt, and I determined that there was no clear idea of where the Oregon Country ended to the north, and that today Oregon Country is often misrepresented as having ending at 54° 40' north.
What would the actual north bound of Oregon Country have been?
The lands the U.S. and Britain were negotiating over had large regions that were poorly explored (that is, poorly explored by Europeans and by those from back east). Representatives of both countries relied on maps that, the farther north one went, were less and less accurate, as well as being essentially unchecked. When diplomats defined the Oregon Country, they were assuming the maps reflected something more or less accurate.
|Hooker and Brown from US Ex. Ex. map of Oregon Country, 1841|
And this was only at 52° north. What other unchecked assumptions lay further north?
Even though there were strong sentiments in both Britain and the U.S. that as little as possible of the Oregon Country should be ceded to the other party, the exact bounds of Oregon Country were never well defined. The Treaty text (the Anglo-American Convention of 1818) stipulates that it is the "North West Coast of America, Westward of the Stony Mountains." Let's look at what these words might mean.
|Watersheds, latitudes and the crest of the Rockies in Oregon Country|
The South bound is pretty clear: it's the 42ndparallel, agreed to be the northern limit of Spanish claims in the 1818 Adams–Onís Treaty.
The East bound relies on there being a feature called the Stony Mountains. Most maps of the period show the Stony Mountains as a thin band of peaks running north-south, which would have made a precise boundary.
|The Arrowsmith map from 1844, showing the Rockies as a single chain|
South of 52°, it's a simple choice of the Atlantic watershed on one side, and the Pacific watershed on the other. But north of 52° one has to choose between the Atlantic-Arctic divide, which wanders off across the high plains to the northeast, or the Pacific-Arctic divide, which continues to follow the core of the range. Assuming you choose the latter, your next conundrum occurs at about 54° 30', where the Pacific-Arctic divide diverges from the Rockies and heads northwest. At this point, large rivers of the Peace River system are rising west of the crest of the range and flowing through it. Here the range has no meaning as a watershed divide at all.
If we stick by the words of the treaty, we are bound to continue following the crest of the Rockies. So Oregon Country north of 54° 30' includes some eastward flowing rivers. And indeed, cartographers of the time, if they ever mapped Oregon Country this far north, drew there line as we have, along the crest of the Rockies.
The North bound is the big mystery. The Treaty did not address it, and here we get into territory that was little travelled and little reported.
Nowadays it's not uncommon for a history map to show Oregon Country as ending at 54° 40' north. They either show this as a line drawn from the Pacific Ocean to the Rocky Mountains by the 1824 treaty between the U.S. and Russia, which is wrong, or they show it as the northern limit of American claims, which is right, but in neither case does this mean that Oregon Country ended here.
54° 40' was not a number that meant anything when the Oregon Country was set up in 1818. It arises for the first time six years later when the Americans and the Russians sign the St. Petersburg Convention of 1824. This treaty mentions 54° 40' as a latitude to separate their respective spheres of influence regarding coastal establishments. The wording of the treaty is “there shall not be formed by the citizens of the United States ... any establishment upon the Northwest Coast of America, nor in any of the Islands adjacent, to the north of fifty-four degrees and forty minutes of north latitude ; and that, in the same manner, there shall be none formed by Russian subjects... south of the same parallel.”
|Eugene Duflot de Mofras's map, 1844|
|Line at 54° 40' on the Duflot de Mofras map|
|Map of Oregon Territory, 1841, Wilkes Expedition|
|Detail of 54° 40' line on Wilkes Expedition map|
Others are more ambiguous. The American "Wilkes Expedition" of 1841 produced an authoritative-looking "Map of the Oregon Territory" on which the Oregon Country ended, at 54° 40', with an unlabelled line in the same style as other international boundaries on the map.
|Jeremiah Greenleaf, 1840, Brattleboro|
American commercial map-makers go further: they colour the land differently on either side of 54° 40', and label the line as "Boundary of Russian Possessions Settled by Convention in 1824" (Jeremiah Greenleaf, Brattleboro, in 1840) or "Boundary of 1824" (Henry Tanner, Philadelphia, in 1833).
|Henry's Tanner's 1833 map of Oregon|
|From Lawrence J. Burpee, editor, AN HISTORICAL ATLAS OF CANADA, Toronto, Thomas Nelson and Sons, 1927|
So the myth grows that the disputed Oregon Country somehow stopped at 54° 40', and in the 20th century you have maps like one from Burpee's Historical Atlas of Canada, 1927, that shows the Oregon boundary running along 54° 40', or this
|Denoyer-Geppert 1941 Historical Oregon Country|
|Oregon Country as we mapped it|
This being the practical limits of Oregon Country for the fur traders at the time, we decided to use the Nass and Finlay Rivers as our boundary. Note that these two rivers do not meet at the divide. Their respective headwaters are about 50 km apart, and occur in close proximity to the headwaters of the Stikine, another Pacific river that reaches the coast farther north. A connecting line had to be drawn using the watershed boundaries, first the Finlay-Skeena, then the Stikine-Skeena, then the Nass-Stikine.