The Arney River is a small river in County Fermanagh, Northern Ireland, feeding from Lower Lough MacNean and into Upper Lough Erne. It meanders through a wide, flat Glacial Trough between the uplands of Fermanagh, Belmore Mountain and the Cuilcagh Mountains. The valley is characterised by wide flat lowlands enclosed by low hills. The Cladagh River drains into the Arney River.