when did they finish building the transcontinental railroad
First Transcontinental Railroad Several years after the end of the Civil War, the competing railroads coming from Missouri finally realized their initial strategic advantage and a building boom ensued. In July 1869, the H&SJ finished the Hannibal Bridge in Kansas City which was the first bridge to cross the Missouri River. This in turn connected to Kansas Pacific trains going from Kansas City to Denver, which in turn had built the Denver Pacific Railway connecting to the Union Pacific. In August 1870, the Kansas Pacific drove the last spike connecting to the Denver Pacific line at Strasburg, Colorado and the first true Atlantic to Pacific United States railroad was completed.