Four coat colours are recognized for Rough Collies: sable and white, where the "sable" ranges from pale tan to a mahogany; tricolour, which is primarily black edged in tan; blue merle, which is mottled gray, White, which is a mainly all-white coat, except for the head, which could be tri, sable or blue.
All have white coat areas, in the collar, parts of the leg, and usually the tail tip.
Some may have white blazes on their faces.
In addition, the American Kennel Club accepts white, where the dog is predominantly white with coloured markings of sable, tricolor, or blue merle on the head and sometimes body patches.
Rough Collies have a blunter face than the smaller, but otherwise very similar Shetland Sheepdog, which is partly descended from the Rough Collie.
The planes of the muzzle and the top of the skull should be parallel in collies, with a slight but distinct stop. (In shelties, the planes are not parallel.)
The downy undercoat is covered by a long, dense, coarse outer coat with a notable ruff around the neck, feathers about the legs, a petticoat on the abdomen, and a frill on the hindquarters.
The size and weight varies among breed standards; male collies can stand 55.8 to 66 cm (22 to 26 in) at the shoulder; the female averages 5 cm (2 in) shorter.
The males are usually in the weight range (50–70 lbs), and the females are usually 5 to 10 lbs less.
Collies in the US are sometimes reported to be over a hundred pounds – a large collie typically weighs no more than 70 pounds.
US and UK standards may differ. The UK standard calls for dogs to be significantly smaller than those under the American Kennel Club.
One of the characteristic features of the Rough Collie is its head. This is light in relation to the rest of the body, and resembles a blunted wedge tapering smoothly from ears to black nose, with a distinct stop and parallel head planes. The muzzle is well rounded, and never square.
There is considerable variation in the colour of the head, however.
The eyes are medium-sized and almond shaped. The ears are supposed to be semi-prick, with the upper third folded over.
Ears which do not 'tip' properly are fairly common, and many collies have their ears taped as puppies (using medical adhesive or paper tape) to encourage them to lay properly – no cutting or surgery is involved. They are similar to a Shetland Sheepdog's, but larger.
Once seen, the contrast between the Rough Collie head and that of a Border Collie is immediately apparent, the latter having a considerably shorter muzzle and a more distinct stop between muzzle and forehead. The ruff is also distinctive in distinguishing the two breeds.