First Transcontinental Railroad
Also called: Pacific Railroad
Lines built from east and west met at Promontory Summit, Utah, linking the Atlantic and Pacific sides of the United States by rail.

Andrew J. Russell / Adam Cuerden · Public domain · Source
Under the Pacific Railway Act of 1862, passed during the Civil War, the Central Pacific built east from California and the Union Pacific west from Nebraska. Chinese workers did much of the hard labour through the Sierra Nevada, while Irish immigrants and discharged soldiers worked the plains. On 10 May 1869 the two lines met and a golden spike was driven.
The railroad hastened western settlement and the integration of the national market, but Native Americans lost their land and the bison and were pushed onto reservations. America’s reach to the Pacific extended toward Asia; in the same years Korea saw the General Sherman incident (1866) and the US expedition of 1871.