Adult Northern leopard frogs have smooth skin that is green or brown and covered with dark brown spots outlined with white rings. Females grow to just over four inches in length; males are slightly smaller at just over three inches.
They live in and near various water sources with abundant vegetation such as wet meadows, marshes, riparian areas and moist, open woodlands. These frogs use the vegetation, such as grasses, sedge, weeds or brush, as cover from predators. During the winter, they need ponds or slow-running streams for hibernation.