The Pacific Railroad refers to a series of railroads built in the 19th century that connected the eastern United States to the western territories. The most notable of these is the First Transcontinental Railroad, completed in 1869, which linked Sacramento, California to Omaha, Nebraska. This monumental project facilitated trade, travel, and the movement of people across the country. The construction of the Pacific Railroad was a significant engineering feat, involving thousands of workers, including immigrants from China and Ireland. It played a crucial role in the expansion of the United States, promoting economic growth and the settlement of the western frontier.