Updated: Oct 30
North America's West Coast shortly before the Oregon Treaty.
"1846::Map of Oregon and the Oregon Question"
Clip: Kendal Mercury (1846)
Between the mid-1700s and the mid-1800s, land in the new world of North America was being claimed, fought for, divided and purchased. If Great Britain, France, Russia, Spain and the newly formed United States of America were not hashing out their land claims on the battlefield, they were busy signing treaties that laid out ownership and boundaries.
"1803::The Louisiana Purchase"
Map: McConnell Map Co. 
The Library of Congress (2009581130)
In 1803, France became the first country to back out of the new world by selling its land interest to the USA at a bargain price of 15 million dollars. French Louisiana's 530 million acres, stretching from the Mississippi River to the Rocky Mountains and from the Gulf of Mexico to the Canadian border East of the Rocky Mountains, was the USA's first major land acquisition that doubled the size of the fledgling country and gave hope for its expansion in the West. But what lay West of the Rocky Mountains remained a concern... and it had to be dealt with.
Map Clip: (tbd)
In 1818, the United States and Great Britain signed a treaty to establish a division at the 49th parallel East of the Rocky Mountains and to allow for joint occupation and settlement of Oregon, the unclaimed area in the West between the Rocky Mountains and the Pacific Coast. The following year, Spain, in a treaty with the United States, became the second country to end its pursuit of the new world when it relinquished all of its claims in the Americas north of the 42nd parallel. In 1825, Russia became the third country to back out of its new world land pursuits by signing a treaty with Great Britain that defined boundaries between Russian America and Great Britain's claims and possessions of the North Pacific and Arctic Coasts. With France, Spain and Russia out of the way, Britain and the United States were the remaining two who, in 1846, just months after the Map of Oregon appeared in an English newspaper, signed the Oregon Treaty that permanently established ownership of Oregon and the 49th parallel as the extended boundary between the United States and British North America to the Pacific Ocean.
"1867::The Alaska Purchase" Map: GW & CB Colton & Co. (1867)
The 1825 Treaty of St. Petersburg, which was to outline the northern claims and possessions of Russia and Great Britain, was so poorly defined along the North Pacific Coast that it led to a decades-long boundary dispute between the two countries. In 1867, long after the Oregon Question was resolved between the USA and Great Britain, Russia finally sold its remaining land interest in Alaska to the USA at a bargain price of 7.2 million dollars. The USA inherited the boundary dispute in their Alaska Purchase, which they later settled in 1903 by arbitration.