The Oregon Country was divided between Britain and the United States at the 49th Parallel.
hope this helps :)
Reference to a 1946 Washington Treaty cannot be found. Perhaps you are referring to the Oregon Treaty, which was signed in Washington, D.C. on June 15, 1846. The Treaty of Oregan ended the boundary dispute concerning the Oregon Country, which had been occupied by Britain and US since the Treaty of 1818.
