In which year did the United States complete the purchase of Oregon?

The United States completed the purchase of Oregon in 1846 through the Oregon Treaty with Great Britain. This treaty settled the boundary dispute between the two nations over the Oregon Territory, which included present-day Oregon, Washington, and parts of Idaho, Wyoming, and Montana. The agreement established the 49th parallel as the border between U.S. and British territories in North America, enabling the U.S. to gain full control over the region, which had been jointly occupied since the 1818 Anglo-American Convention.

The significance of this purchase lies in its role in the expansionist ethos associated with Manifest Destiny, where many Americans believed it was their divine right to expand across the continent. While some of the other years presented in the choices hold historical significance in relation to various treaties or events surrounding U.S. territorial expansion, 1846 is specifically noted for the conclusion of the Oregon territorial dispute.