The Wyoming Valley is a historic industrialized region of northeastern Pennsylvania once famous for fueling the industrial revolution in the United States with its many anthracite coal mines. As a metropolitan area, it is known as the Scranton/Wilkes-Barre area, the 95th-largest metropolitan area in the United States. It is called the "Scranton/Wilkes-Barre Metropolitan Area" after its principal cities, Scranton and Wilkes-Barre, and makes up its own unique physiographic province, the Anthracite Valley in the geology of Pennsylvania.