The Pony Express was a fast mail service crossing the North American continent from St. Joseph, Missouri, to Sacramento, California from April 1860 to October 1861. Messages were carried on horseback relay across the prairies, plains, deserts, and mountains of the Western United States. It briefly reduced the time for mail to travel between the Atlantic and Pacific coasts to around ten days.
By traveling a slightly shorter route and using mounted riders rather than stagecoaches, the founders of the Pony Express hoped to establish their service as a faster and more reliable conduit for the mail and win away the exclusive government mail contract.
The Pony Express demonstrated that a unified transcontinental system could be built and operated continuously the year around — something that had previously been regarded as impossible. Since its replacement by the First Transcontinental Telegraph, the Pony Express has entered the romance of the American West. Its reliance on the ability and endurance of the individual riders and horses over technological innovation is part of "American rugged individualism".