Lough MacNean (from Irish: Loch Mac nÉan, meaning "Mac nÉan's lake") is a large freshwater lake on the border between Northern Ireland and the Republic of Ireland. It is in two parts. Lower Lough MacNean (or Lough Nilly), the smaller eastern lake, is wholly within County Fermanagh (in Northern Ireland). Upper Lough MacNean, the larger western lake, is split between Fermanagh, County Cavan and County Leitrim (in the Republic of Ireland). On the strip of land between the two lakes are the villages of Belcoo (Fermanagh) and Blacklion (Cavan). A river runs between the villages, linking the eastern and western lakes.