It's an island off Virgina. Yes the horses are "wild" and there's supposed to be an annual migration or something when they will be rounded up and led to another part of the island or something. So people go there to watch the horses swim/drown.... depending on what you find entertaining.
What I don't understand is that the islands are not that big and the horses don't get to venture onto the main land, so what's keeping them alive? I don't think the vegetation on the island alone can sustain the horses. If they are indeed secretly fed by humans, then the are not wild!