The Kentucky Derby is a Grade I stakes race for three year-old Thoroughbred horses, held annually in Louisville, Kentucky, on the first Saturday in May, capping the two-week-long Kentucky Derby Festival. The race is one and a quarter miles (2 km) at Churchill Downs. Colts and geldings carry 126 pounds (57.2 kg) and fillies 121 pounds (54.9 kg). The race is known in the United States as "The Most Exciting Two Minutes in Sports" for its approximate duration, and is also called "The Run for the Roses" for the blanket of roses draped over the winner. It is the first leg of the United States Triple Crown of Thoroughbred Racing and is followed by the Preakness Stakes then the Belmont Stakes.

The Kentucky Derby is one of the USA's oldest Thoroughbred horse races (the Travers Stakes being the oldest, first ran in 1864). From the time the region was settled, the fields of the Bluegrass region were noted for producing superior racehorses. In 1872, Col. Meriwether Lewis Clark, Jr., grandson of William Clark of the Lewis and Clark expedition, traveled to England, visiting the Epsom Derby, a famous race that had been running annually since 1780. From there, Clark went on to Paris, France, where in 1863, a group of racing enthusiasts had formed the French Jockey Club and had organized the Grand Prix de Paris, which at the time was the greatest race in France.

Returning home to Kentucky, Clark organized the Louisville Jockey Club for the purpose of raising money to build quality racing facilities just outside of the city. The track would soon become known as Churchill Downs, named for Meriwether Lewis Clark Jr.'s relatives, John and Henry Churchill, who had provided the land for the racetrack. Officially, the racetrack was incorporated as Churchill Downs in 1937.