The document summarizes key events in American history related to westward expansion between the late 1800s and early 1900s. It describes how the culture of Plains Indian tribes declined as white settlers moved onto their lands, forcing tribes onto reservations. Settlers engaged in mining, ranching and farming on the Great Plains, transforming the land, despite facing many hardships. Farmers organized through alliances and populism to advocate for their economic interests against railroads and other industries they felt were exploiting them.