Those who were not selected Tuesday are also noteworthy, the Louisville Courier-Journal reports. None of the 12 contemporary finalists for places in the Hall of Fame achieved the threshold of getting 75 percent support from racing writers, officials and track public relations people.
The National Museum of Racing introduced the 75 percent rule in 2005 because of complaints by racing writers that the Hall of Fame had become too easy to get into. Last year, only trainer Nick Zito made the cut.
A formal ceremony is scheduled Aug. 7 in Saratoga Springs.
Hanford, now retired as a track official, trained only one star horse as manager of Allaire du Pont's stable. But Kelso was named Horse of the Year five times and won the Jockey Club Gold Cup two years in a row.
Boland won the Kentucky Oaks and the Derby as a 16-year-old in 1950, going on to win almost every major U.S. race in his 19-year career.
Cougar II from Chile, owned by Mary Louise Bradley, was the first foreign-bred horse to win more than a million dollars in U.S. racing.