 These valleys include Teesdale and Weardale.The area covers roughly one third of County Durham and is its least populous area.There are just a few market towns within the area—Barnard Castle, Consett, Middleton-in-Teesdale, Stanhope, Tow Law, and Wolsingham,—though some also consider the Durham Dales to extend as far east as Bishop Auckland and Crook.