From the Churchill Downs Media Team:

 

HOW TO GET INTO THE KENTUCKY DERBY STARTING GATE – The Road to the Kentucky Derby Presented by Woodford Reserve is a series of races that awards points to the Top 4 finishers in each race. The top 18 point earners will earn a spot in the starting gate for the 147th running of the Kentucky Derby Presented by Woodford Reserve (Grade I), which is rescheduled for Saturday, May 1, 2021. One invitation will be extended to the top point earners in the Europe Road to the Kentucky Presented by Woodford Reserve and one invitation will be extended to the top point earners in the Japan Road to the Kentucky Derby Presented by Woodford Reserve. The Kentucky Derby field has been limited to 20 starters since 1975. At least 20 horses have entered the 1 1⁄4-mile race for 3-year-olds in 19 of the last 22 years and every year from 2004-19.

20201205 Road to the Kentucky Derby Leaderboard