Armagh is a county in Northern Ireland (Ulster) surrounded by Monaghan, Tyrone, Lough Neagh, Down, and Lowth. The north-west of the county is undulating and fertile. The northern part, bordering on Lough Neagh, consists principally of extensive bogs. On the southern border is a range of barren hills. The chief rivers are the Blackwater, which separates it from Tyrone; the Upper Bann, which discharges itself into Lough Neagh; and the Callan, which falls into the Blackwater. There are several small lakes. The county was traditionally associated with the manufacture of linen.