Answer:
The countries that claimed the Oregon Territory as a result of the Adams-Onis Treaty were the United States and the British Empire.
Explanation:
The Oregon Territory was the designation of the western region of North America between latitudes 42° and 54° 40' North and that went from east to west, from the Rocky Mountains to the Pacific Ocean. This territory is now divided between the Canadian province of British Columbia and the US states of Oregon, Washington and Idaho, plus the western part of Montana and a western part of Wyoming.
The zone was disputed with the Spanish Empire (up to the Adams-Onis Treaty in 1819 which established the southern border at 42º N parallel) and then with the British Empire (up to the Oregon Treaty in 1846 which divided the region into two along the 49th parallel).
