The tail is relatively long and sharply bicolored, white beneath and dark above. The soft fur of the deer mouse varies in colour from a golden brown to a pale grey on the back, while the underparts are white, including the underside of the tail.
Deer mice have four toes on the forefeet and five toes on the hind feet.
It can be found in forests, prairies, and deserts, but is not found where the ground is continually wet. Deer mice do not usually occur in urban areas. Their natural habitat is in rural and semi-rural areas, where they inhabit fields, pastures, and various types of vegetation found around homes and outbuildings. The deer mouse builds a spherical nest by shredding materials such as bark, grass, hair, string, and the fluff from cattails into a soft, warm bed with one main entrance. The nesting site can be found anywhere there is a cavity or opening such as under rocks or wood piles, or in empty bird's nests.