American railroad expansion refers to the rapid growth of the railroad network in the United States during the 19th century. This expansion was crucial for connecting distant regions, facilitating trade, and promoting westward migration. The completion of the Transcontinental Railroad in 1869 marked a significant milestone, linking the eastern and western parts of the country. The expansion was driven by technological advancements and government support, including land grants and financial incentives. Railroads played a vital role in the industrialization of America, enabling the movement of goods and people across vast distances, which contributed to the nation's economic growth and development.