After 1815 , the United States shifted its attention away from foreign policy to internal development . With the defeat of the eastern Indians in the War of 1812 , American settlers moved in great numbers into the rich farmlands of the Midwest . Westward expansion was mostly undertaken by groups of young families . Daniel Boone was one frontiersman who pioneered the settlement of Kentucky . In the 1830s , the federal government forcibly deported the southeastern tribes to their own reservations in the Indian territory ( now Oklahoma ) via the " Trail of Tears " . There they received annual subsidies of food and supplies
Trail of Tears
Trail of Tears
History of the United States (1789–1849)