Meriwether Lewis Clark, Jr., who built Churchill Downs in Louisville, wanted his track to have a race that would rival England's Epsom Derby. After visiting England to study both its tracks and its races, he established the Kentucky Derby, which was first run on May 17, 1875. Except for 1879 through 1895, when it was 1½ miles, the Derby has always been run at 1¼ miles.

The Kentucky Derby was just another regional race until 1902, when Colonel Matt J. Winn took over the track. Although he had seen every Kentucky Derby since the beginning, Winn knew little about horse racing or running tracks, but he was a very good promoter.

After raising money to save Churchill Downs from bankruptcy, Winn began making frequent trips to New York, then the center of American racing, to persuade owners to enter their horses in the Kentucky Derby. His persistence paid off. By 1920, the Derby had become the best-known race in North America and it was attracting the top three-year-olds from all over the country.

The first race in the Triple Crown, the Derby is run on the first Saturday in May. A whole week of festivities is built around the race, drawing socialites, celebrities, and royalty among participants who come to see and be seen, as much as to watch the race. Millions who cannot attend the live events watch the televised Kentucky Derby race.

Hard Spun was the early leader in the 2007 Kentucky Derby race, but was overtaken in the last furlough by a horse named Street Sense .