Eastern cottontail rabbits are smaller than ordinary domestic rabbits, weighing about 4kg, with a body length of 355-485 mm and a tail length of 15-60 mm. The eastern cottontail rabbit has a shorter head, larger eyes, less large ears than the head, no black edges, short hairs on the outside of the ears and slightly longer hairs on the inside. The claws are stout and sharp, covered with fur.

The body of the eastern cottontail rabbit is gray-brown to reddish brown, and the lower body White or pale yellow, the latter usually red or black. The upper part of the tail is brown and the lower part of the tail is white. In summer, the back of the body is yellow-brown, the ears are dark brown, and the belly of the body is pale gray. During winter, some individual hair tips turn black or white.