High Quality Content by WIKIPEDIA articles! The Derby Stakes, popularly known as The Derby, internationally as the Epsom Derby, and under its present sponsor as the Investec Derby, is a Group 1 flat horse race in Great Britain open to three-year-old thoroughbred colts and fillies. It is run at Epsom Downs over a distance of 1 mile, 4 furlongs and 10 yards (2,423 metres), and is scheduled for early June each year.