While the European powers expanded their authority and wealth through imperialism and colonialism in far-flung empires abroad, the United States focused its attention on its own western lands. From the U.S. Army attack on the remainder of the Comanche empire to the conquest of the Black Hills, whites pushed Indians aside as they moved West. As posited by Frederick Jackson Turner, American exceptionalism stressed how the history of the United States differed from that of European nations, citing America’s western frontier as a cause. Yet expansion in the trans-Mississippi West involved the conquest, displacement, and rule over native peoples—a process best understood in the global context of imperialism and colonialism. (See “Beyond America’s Borders.”)

The U.S. government, through trickery and conquest, pushed tribes off their lands (Map 17.1) and onto designated Indian territories or reservations. The Indian wars depleted the Native American population and handed most Indian land to white settlers. The decimation of the bison herds pushed the Plains Indians onto reservations, where they lived as wards of the state. Thus did the United States, committed to an imperialist, expansionist ideology, colonize the West.