The document discusses the reasons for and impacts of western expansion and settlement of the Great Plains in the United States during the late 19th century. It describes how the Homestead Acts of 1862 and later acts aimed to encourage migration to the Plains by offering settlers free land if they lived on and improved it for a period of years. The railroad companies also promoted settlement to increase passenger and freight traffic on their newly built transcontinental lines across the Plains. As a result of these policies and promotions, over 2.5 million acres were claimed and millions of settlers moved West, transforming the Plains.