Derby Day - View over course showing crowds.. Part of Box 247 Boswell Collection.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 England open to three-year-old thoroughbred colts and fillies. It is run at Epsom Downs in Surrey over a distance of one mile, four furlongs and 10 yards (2,423 metres), and is scheduled for early June each year.