According to Ann W. Whitney and Caroline C. Bullock in Folk-Lore from Maryland, in 1887 two men on horseback were near Warfieldsburg's Ore Mine Bridge, in Carroll County, saw a large black dog on the other side of a fence. The dog passed through the fence, crossed the road, passed through a fence on the other side, and disappeared from view. Whitney and Bullock record that one of the men was amazed at the dog's size - apparently, the fact that it passed through two fences wasn't worthy of his mention.
They also record that a man was told that he could see a phantom dog if he stood underneath a tree near a bridge for an hour. He did so, and sure enough, the dog appeared. He stated that the dog then followed him for a little way. This is similar to the British black dogs, which often follow travellers. Another sighting which bears a parallel to British lore was one by a man driving a wagon down the road, who said that he saw the phantasmal dog dragging a chain. Barghest of the Yorkshire Moors is reputed to engage in just such a chain-dragging activity. This is also a feature of Cadejo of Central American lore, a black hound with hooved feet.
The black dog of Warfieldsburg can supposedly only be seen by an individual once. A cracking whip near the dog will make it vanish. This theory was unsuccessfully tested in the 1920s by one witness, whose whip passed right throught the dog.
The sadly deceased Mark Chorvinsky has recorded a sighting of a phantom hound near Warfieldsburg in 1975 ("Phantom Dogs in Maryland", Strange Magazine 19). Several people driving along the road heard a thud as the car impacted a large black dog. Some of the witnesses distinctly felt the creature underneath the wheels. Yet when the car stopped, the passengers "were amazed to see the dog standing on its huge paws. The beast bared its teeth, showing an ugly red mouth, then vanished as suddenly as it had appeared."