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)).

pony, small horse, officially any horse under 14.2 hands (58 in./145 cm) high. Most ponies are of Celtic origin. They are noted for their extreme hardiness and gentle natures. Some ponies are only 26 in. (65 cm) high. See Shetland pony; Welsh pony.

Welsh pony, breed of small horse of European origin. First bred primarily in Saxony, it later became localized in Wales. Although the breed is of ancient type, it presently bears traces of the Arabian horse and shows influences of the Thoroughbred horse. It is a popular children's pony and has been used extensively for light labor, especially in the harness, having trotting tendencies similar to those of the Standardbred horse. The Welsh pony is taller than the Shetland pony, averaging just over 12 hands (48 in./120 cm). It is usually of solid color, with grays, whites, and chestnuts predominating.

Shetland pony, smallest breed of horse, originating in the Shetland Islands some 200 mi (322 km) N of Scotland. The Shetland resembles a miniature draft horse and has long been used for working purposes. The most popular of the ponies, it has a gentle disposition and is therefore a favorite mount for children. Its official size is less than 46 in. (117 cm) high, and some Shetlands are scarcely more than 2 ft (61 cm). The coat is characteristically long and shaggy and may be any color, although many Shetlands have irregular dark and white patches.

Any of several breeds of small horses standing less than 14.2 hands (58 in., 147 cm) high and noted for gentleness and endurance. Among the common pony breeds are the Shetland; the stylish and hardy Welsh; the high-stepping Welsh Cob; the Exmoor and Dartmoor, natives of the English moors that are used to breed polo ponies; and the Highland, a thick, gray saddle animal.

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Breed of pony that originated in Scotland's Shetland Islands. Well adapted to the islands' harsh climate and scant food supply, Shetlands were used as pack horses. Around 1850 they were taken to England to work in coal mines and to the U.S., where a more refined pony suitable for children was developed. Except for certain dwarf ponies, the Shetland is the smallest breed of horse. Its average height is about 40 in. (102 cm; Shetlands are not measured in hands). Shetlands are long-lived and need little care; they are gentle and even-tempered if properly trained.

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