The First Transcontinental Railroad was a significant engineering project completed in 1869, connecting the eastern and western United States. It linked Sacramento, California to Omaha, Nebraska, allowing for faster transportation of goods and people across the country. The project was primarily built by two companies: the Central Pacific Railroad and the Union Pacific Railroad. Construction began in the 1860s, utilizing thousands of workers, including many immigrants. The railroad was completed on May 10, 1869, when the last spike, known as the Golden Spike, was driven into the ground at Promontory Summit, Utah. This achievement transformed travel and commerce in America.