Map showing the Union Railway and connecting railroads, 1882.
The Union Pacific Railroad emerged in 1862 under the Pacific Railroad Act. The Act of Congress initiated the construction of railroads west of the Missouri River, to harness control of western resources during the American Civil War.
The Union Pacific was constructed west from Council Bluffs, Iowa. At the same time the Central Pacific was laid out east from San Francisco. The two lines met up at Promontory Summit in Utah in 1869 to much fanfare.
This highly detailed relief map of the western United States was published in 1882 by G.W. & C.B. Colton & Co. It shows cities, towns, boundaries, waterways, mountains, and railroads, emphasizing the main line.