Oregon was originally a portion of land between the Rocky Mountains and the Pacific Ocean that Americans and British agreed to jointly occupy in 1818. Over decades, settlers went to Oregon for various reasons like becoming missionaries, starting farms, or trading furs. In 1846, the US and Britain signed a treaty giving the United States control over Oregon, Washington, Idaho, part of Montana, and Wyoming. This gave the US land from the Pacific to the Atlantic oceans and encouraged further settlement, some of which occurred along the difficult 2,000 mile Oregon Trail.