Much of the Ardennes is covered in dense forests, with the hills averaging around in height but rising to over in the boggy moors of the High Fens region of south-eastern Belgium. The region is typified by steep-sided valleys carved by swift-flowing rivers, the most prominent of which is the Meuse. Its most populous cities are Verviers in Belgium and Charleville-Mézières in France, both exceeding 50,000 inhabitants. The Ardennes is otherwise relatively sparsely populated, with few of the cities exceeding 10,000 inhabitants. (Exceptions include Belgium's Eupen and Bastogne.)
