a US mail service in the Old West, using riders and horses (not ponies). It operated from April 1860 to October 1861, between St Joseph, Missouri, and Sacramento, California, a distance of 1 966 miles/3 163 kilometres, which the riders could complete in 10 days by changing horses at regular stations along the way. Buffalo Bill was one of the riders. The service came to an end when a telegraph line (= a device for sending messages on electric wires) was completed. The Pony Express National Historic Trail was established in 1992.