In the 1840s, slavery moved to the center stage of american politics. it did do as a result of the nation's territorial expansion. by 1840, with the completion of indian removal, virtually all of the land east of the mississippi river was in white hands. the depression that began in 1837 sparked a large migration of settlers further west. some headed to oregon, whose willamette valley was reputed to be one of the continent's most beautiful and fertile regions. until the 1840s, american presence in the area had been limited to few fur traders and explorers. but between 1840 and 1845, some 5,000 emigrants made the difficult 2,000 mile journey by wagon train to oregon from jumping-off places on the banks of the missouri river. by 1860, nearly 300,000 men, women and children had braved disease, starvation and the natural barrier of the rocky mountains - along with occasional indian attacks to travel overland to oregon and california. during most of the 1840s, the u. s. and g. b. jointly administered oregon and utah was still part of mexico. this did not stop americans from settling either region. national boundaries meant little to those whom moved west. the 1840s, witnessed an intensification of the old belief that god intended the american nation to reach all the way to the pacific ocean. this expansionist spirit was manifest destiny.