For 10 points, name this region of the Pacific Northwest, the namesake of a trail used by pioneers.
After the death of fur trapper Ewing Young, this region was left without a government until the Champoeg Meetings created the Organic Laws, which set up a provisional government. John McLoughlin is seen as the father of this region, and the Whitman Massacre here sparked the Cayuse War. Henry James Warre and Mervin Vavasour were sent to scout this region in case a war broke out over it, but it never came to that, although Lyman Cutler's shooting of an animal did spark the bloodless Pig War here. Missouri Senator Lewis Linn was a champion of annexing this region, and a dispute over the boundary of this region led to the slogan "Fifty-four Forty or Fight!" but James Polk settled for the 49th parallel as its northern border in an 1846 treaty with Great Britain. For 10 points, name this region of the Pacific Northwest, the namesake of a trail used by pioneers.
After the death of fur trapper Ewing Young, this region was left without a government until the Champoeg Meetings created the Organic Laws, which set up a provisional government.
{Oregon} Territory [or {Oregon Country}]