The First Transcontinental Railroad was a significant railway project in the United States, completed in 1869. It connected the eastern U.S. rail network with the Pacific coast, facilitating travel and trade across the country. The railroad was built by two main companies: the Central Pacific Railroad and the Union Pacific Railroad. Construction began in the 1860s, with workers facing numerous challenges, including harsh weather and difficult terrain. The railroad was officially completed on May 10, 1869, at Promontory Summit in Utah, where the two rail lines met. This achievement greatly impacted the economy and settlement patterns in the West.