The Oregon Boundary Dispute was a territorial conflict in the early 19th century between the United States and Great Britain over the Pacific Northwest region, particularly the area known as Oregon. Both nations claimed the land, with the U.S. asserting its rights based on the Louisiana Purchase and the Oregon Trail, while Britain relied on its exploration and fur trading activities. The dispute was resolved with the signing of the Oregon Treaty in 1846, which established the boundary at the 49th parallel. This agreement allowed the U.S. to gain control of the present-day states of Oregon, Washington, and parts of Idaho and Montana.