There have been many reported sightings of so-called "black panthers" in Kentucky (and other states as well) despite the fact that they aren't supposed to be here. "Panther" is a generic term that refers to any number of large black cats in general, and if there really are black ones in our state, they are most likely rare melanistic colour mutation of any number of species.
According to Wikipedia:
"There are no authenticated cases of truly melanistic cougars (pumas). Melanistic cougars have never been photographed or shot in the wild and none has ever been bred. There is wide consensus among breeders and biologists that the animal does not exist."
However, it then immediately goes on to state:
"Black cougars have been reported in Kentucky and in the Carolinas."
The photo above is one such example.
On the other hand, black Bobcats, while also rare, are acknowledged to exist, and although they technically do not qualify as panthers, I don't think the average person who spots one is going to care about the finer distinctions.