It is said to be the longest continuously running Thoroughbred horse farm in Kentucky, 365-acre (1.48 km2) established in 1867 by American Civil War Colonel Ezekiel Field Clay.
[1] Colonel Ezekiel Clay (1840–1920), whose father, Brutus J. Clay, was a member of the Kentucky House of Representatives and the United States House of Representatives and a breeder of Thoroughbreds and champion cattle.
In the early part of the 1870s Ezekiel Clay formed what became a successful partnership with Catesby Woodford (d. age 74 in 1923) who owned the neighbouring Raceland Farm.
Both the partnership and Clay's Runnymede operation produced a number of top line horses.
Racing Hall of Fame inductees Miss Woodford, Hanover, Ben Brush, and Roamer were bred at Runnymede Farm.