<P> The Triple Crown of Thoroughbred Racing, often shortened to Triple Crown, comprises three races for three - year - old Thoroughbred horses . Winning all three of these Thoroughbred horse races is considered the greatest accomplishment in Thoroughbred racing . The term originated in mid-19th century England and nations where thoroughbred racing is popular each have their own Triple Crown series . </P> <P> In the United States, the three races that make up the Triple Crown are: </P> <Ol> <Li> Kentucky Derby, run over the 1 ⁄ - mile (2.0 km) dirt track at Churchill Downs in Louisville, Kentucky </Li> <Li> Preakness Stakes, run over the 1 ⁄ - mile (1.9 km) dirt track at Pimlico Race Course in Baltimore, Maryland </Li> <Li> Belmont Stakes, run over the 1 ⁄ - mile (2.4 km) dirt track (the longest in U.S. thoroughbred racing) at Belmont Park in Elmont, New York, just east of New York City </Li> </Ol> <Li> Kentucky Derby, run over the 1 ⁄ - mile (2.0 km) dirt track at Churchill Downs in Louisville, Kentucky </Li>

What are the lengths of the 3 triple crown races