The period of American history known as the "Indian Wars" saw the expansion of the United States into land once owned and settled by it original inhabitants, Native Americans. Skirmishes, raids, massacres, and conflicts occurred as Native Americans, abused and mistreated by the government, fought U.S. soldiers for land.
European-American settlers, whose ancestors came from Europe (as mine did), saw land to the west of the original 13 colonies as having great potential for growing crops, homesteading, mining, and ranching. The only problem with moving into that land was that it belonged to Native Americans. Greed played a big part in the racism of European-Americans who coveted Native American land.
