 Negotiations between the two powers continued, resulting in the Treaty of 1818, which defined the Canada–United States border west of the Great Lakes.The boundary was set at the 49th parallel to the Rocky Mountains, while the territory to the west of the mountains, known as Oregon Country, would be jointly occupied.The agreement represented a turning point in United Kingdom–United States relations, as the U.S. turned its attention to its southern and western borders and British fears over American expansionism waned.