The document discusses westward expansion and the conflicts that arose between white settlers and Native American tribes on the Great Plains. It describes how tribes like the Sioux inhabited and roamed the plains, claiming the land as their hunting grounds. However, the increasing number of white settlers traveling west on the Oregon Trail, the construction of the Transcontinental Railroad, the Homestead Act encouraging further settlement, and the discovery of gold and other resources led to more conflicts over land with Native Americans and a series of Indian Wars. The Wounded Knee massacre in 1891 marked one of the final major conflicts as tribes were increasingly confined to reservations.