Wilkes-Barre is a city in the Commonwealth of Pennsylvania and the county seat of Luzerne County. It is one of the principal cities in the Scranton–Wilkes-Barre–Hazleton, PA Metropolitan Statistical Area. Located at the center of the Wyoming Valley, it is second in size to the nearby city of Scranton. The Scranton–Wilkes-Barre–Hazleton, PA Metropolitan Statistical Area had a population of 563,631 as of the 2010 Census, making it the fourth-largest metro/statistical area in the state of Pennsylvania. Wilkes-Barre and the surrounding Wyoming Valley are framed by the Pocono Mountains to the east, the Endless Mountains to the north and west, and the Lehigh Valley to the south. The Susquehanna River flows through the center of the valley and defines the northwestern border of the city.