How did the United States and Britain agree to split the land?

Treaty of 1818, was an international agreement that was signed in 1818 between the United States and the United Kingdom. It was signed during the administration of President James Monroe to settle present boundary concerns between the two nations. The treaty permitted dual enterprise and settlement of the Oregon County known to the British and in Canadian history as the District of Columbia of the Hudson’s Bay Company that includes the southern part of New Caledonia. The two nations settled on a boundary line including the 49th parallel north because it would be easier to survey a straight-line boundary than the boundaries founded on watersheds that already exists.