This list of mammals in Pennsylvania consists of 66 species currently believed to occur wild in the state. This excludes feral domesticated species such as feral cats and dogs.
Several species recently lived wild in Pennsylvania, but are now extirpated (locally, but not globally, extinct). They are the marsh rice rat (Oryzomys palustris), eastern wolf (Canis lycaon), American marten (Martes americana), wolverine (Gulo gulo), cougar (Puma concolor), Canada lynx (Lynx canadensis), moose (Alces alces), and bison (Bison bison).
Order: Didelphimorphia
Family: Didelphidae
One species of opossum occurs in Pennsylvania.
Order: Eulipotyphla
Family: Soricidae
Seven species of shrews live in Pennsylvania.
Family: Talpidae
Three species of moles occur in Pennsylvania.
Order: Chiroptera
Family: Vespertilionidae
Eleven species of evening bats occur in Pennsylvania.
Order: Lagomorpha
Family: Leporidae
Three species of rabbits and hares occur in Pennsylvania.
Order: Rodentia
Family: Castoridae
One species of beaver occurs in Pennsylvania.
Family: Myocastoridae
One species of porcupine occurs in Pennsylvania.
Family: Zapodidae
Two species of jumping mice occur in Pennsylvania.
Family: Cricetidae
Nine species of voles and New World rats and mice occur in Pennsylvania.
Subfamily Arvicolinae (lemmings, voles, and muskrats)
Subfamily Neotominae (North American rats and mice)
Family: Muridae
Three species of Old World rats and mice occur in Pennsylvania.
Family: Sciuridae
Eight species of squirrels, chipmunks, and marmots occur in Pennsylvania.
Subfamily Sciurinae (tree squirrels and flying squirrels)
Subfamily Xerinae (chipmunks and ground squirrels)
Order: Carnivora
Family: Felidae
One species of cat occurs in Pennsylvania.
Family: Canidae
Three species of canids occur in Pennsylvania.
Family: Ursidae
One species of bear occurs in Pennsylvania.
Family: Mephitidae
Two species of skunks occur in Pennsylvania.
Family: Mustelidae
Seven species of mustelids occur in Pennsylvania.
Family: Procyonidae
One species of raccoon occurs in Pennsylvania.
Order: Artiodactyla
Family: Cervidae
Two species of deer occur in Pennsylvania.