It was never fully standardized, but the American Boarhound was bred to a consistent type up until the first two decades of the 20th century, when the breed became very rare to find in its pure form, due to numerous crossings with American Bulldogs, Pit Bulls, Coonhounds, Plott Hounds and other popular breeds. Some fanciers trace certain giant bloodlines of the American Pit Bull Terrier breed to the Old Southern Boarhound, but this theory needs more research. This large muscular dog usually had cropped ears and a docked tail, but it isn't certain whether this was done for fighting purposes or not.
The coat was short and flat, most commonly black or dark brindle in colour, with white markings found on its face, chest and feet. The height varied from 24 inches to well over 30 inches at the withers.