The hair coat of the Katahdin varies in length and texture among individuals and can be any color or color combination. It generally consists of coarse outer hairfibers and an undercoat of fine wooly fibers that becomes very thick and longer if cold weather sets in and day length decreases. This undercoat and some hair naturally sheds as temperature and day length increase seasonally, leaving a shorter, smooth summer coat. While some uses may be found for the shed fiber, it is generally not harvested. It usually takes at least 3 generations, depending on the type of wool sheep parentage, to obtain a lamb with a shedding hair coat and other purebred characteristics.
Rams are distinctly masculine and well muscled, ewes strong and feminine.
Variety in facial characteristics is expected. Polledness is preferred, but horns and scurs are acceptable. Eyes are wide set and ears are neither drooping nor erect. Lower teeth meet the dental pad evenly. A ram's neck may be covered by a mane of hair.