The impact of the building of the Transcontinental Railroad was transformative for the United States, facilitating economic growth, migration, and the expansion of territory. Completed in 1869, the railroad connected the eastern and western parts of the country, significantly reducing travel time and costs for goods and people. It encouraged westward expansion, making remote areas more accessible and promoting settlement, particularly in the West. The railroad also enabled industries to flourish, fostering trade and commerce. However, it also had detrimental effects on Native American communities, leading to displacement and loss of lands, thereby reshaping the social and economic landscape of the nation.