pony express, in U.S. history, relay mail service. At its inception in Apr., 1860, the pony express operated between St. Joseph, Mo., the western end of a telegraph line, and Sacramento, Calif. Riders carried the mail a distance of nearly 2,000 mi (3,200 km) in about eight days, often traveling through hostile Native American territory. Stations where the riders changed horses were roughly 10 to 15 mi (16-24.1 km) apart. After a rider had covered a certain distance, the mail was turned over to another rider; this continued until the destination was reached.
The pony express was operated by the freighting firm of Russell, Majors, and Waddell. As a business venture, it was unsuccessful. Before the pony express, letters to and from California had been carried by ships, wagon trains, and stagecoaches and had required much more time for the journey. The first telegram to San Francisco was transmitted Oct. 24, 1861, and the pony express was then gradually discontinued. Its existence was brief but picturesque, and the pony express lives in legend as well as in history. In 1992 the Pony Express National Historic Trail, which covers the entire route followed by pony express riders, was designated part of the National Trails System (see National Parks and Monuments (table)).