The Pony Express was a fast mail service crossing the Great Plains, the Rocky Mountains, and the High Sierra from St. Joseph, Missouri, to Sacramento, California, from April 3, 1860 to October 1861. It became the west's most direct means of east-west communication before the telegraph and was vital for tying California closely with the Union just before the American Civil War. The Pony Express was a mail delivery system of the Leavenworth & Pike's Peak Express Company of 1849 which in 1850 became the Central Overland California and Pikes Peak Express Company. This firm was founded by William H. Russell, Alexander Majors, and William B. Waddell all of whom were notable in the freighting business.
This original fast mail 'Pony Express' service had messages carried by horseback riders in staged relays to stations (with fresh horses and riders) across the varied terrain of the Western United States. During its 18 months of operation, it reduced the time for messages to travel between the Atlantic and Pacific coasts to about ten days, with telegraphic communication covering about half the distance across the continent and mounted couriers the rest.