"Stewball" was the name of an 18th-century British racehorse, most famous as the subject of a broadsheet ballad and folk-song.
The horse was foaled in 1741 and originally owned by Francis, 2nd Earl of Godolphin. His name has been recorded as "Squball", "Sku-ball" or "Stewball". He won many races in England and Ireland. The Irish turf calendar states that he won six races worth £508 in 1752, when he was eleven years old, and was the top-earning runner of that year in Ireland. His most famous race took place at the curragh of Kildare (near Dublin), which is generally the subject of the song of the same name. Based on the horse's name, Skewball was likely a "skewbald" horse, i.e.: a horse with a coat made up of white patches on a non-black base coat, such as chestnut or bay.
The song was recorded by Lead Belly, Woody Guthrie, A. L. Lloyd, Martin Carthy, Steeleye Span, The Greenbrier Boys, the Chad Mitchell Trio, Joan Baez and Peter, Paul and Mary.