The building of the Transcontinental Railroad, completed in 1869, had a transformative impact on the United States. It facilitated the movement of people, goods, and resources across the vast expanse of the country, significantly reducing travel time and costs. This connectivity spurred economic growth, enabling the expansion of industries and agricultural development. Additionally, it promoted westward expansion and settlement, leading to significant demographic shifts. However, it also had detrimental effects on Native American communities, leading to loss of land and disruptions to their traditional lifestyles, raising complex social and ethical issues that continue to resonate.