The 6.3/15 rating and share means 6.3 percent of all TV homes were tuned to the race, with 15 percent of the sets in use at the time of the Preakness tuned to the win by California Chrome.
Not surprisingly, Baltimore was the top market with a 17.2 rating and 39 share -- that was 10 percent higher than last year.
But it didn't beat Louisville by much with its 16.6/33.
Other Top 10 markets for the telecast:
Fort Myers 11.3/23
Nielsen ratings data provided by NBC Sports.