The early history of Fort Riley is closely tied to the movement of people and trade along the Oregon and Santa Fe trails. These routes, a result of then-popular United States doctrine of "manifest destiny" in the middle of the 19th century, prompted increased American military presence for the protection of American interests in this largely unsettled territory. During the 1850s, a number of military posts were established at strategic points to provide protection along these arteries of emigration and commerce.