The ruffed grouse (Bonasa umbellus) is a medium-sized grouse occurring in forests from the Appalachian Mountains across Canada to Alaska. It is the most widely distributed game bird in North America. It is non-migratory.
The ruffed grouse is sometimes incorrectly referred to as a "partridge", an unrelated phasianid, and occasionally confused with the grey partridge, a bird of open areas rather than woodlands.
The ruffed grouse is the state game bird of Pennsylvania, United States.