Lough MacNean

Lough MacNean is a large freshwater lake on the border between Northern Ireland and the Republic of Ireland.
It is in two parts. Lower Lough MacNean, the smaller eastern lake, is mainly in County Fermanagh, with a smaller part in County Cavan. Upper Lough MacNean, the larger western lake, is split between counties Fermanagh, Cavan and Leitrim. On the strip of land between the two lakes are the villages of Belcoo, County Fermanagh and Blacklion, County Cavan. A river, named the Belcoo River, runs between the villages, linking the eastern and western lakes. The river is approximately one mile long, and throughout its length forms the international border.
The shape of Lough MacNean changed during the 1960s when a major draining operation took place; before this, the lake was used for eel fishing, but dredging during the drainage process decimated their numbers.

Islands

;Upper Lough MacNean

Bilberry Island
Garrow Islands
Inishkeen
Inishteig
Kilrooskagh Island
Patrick's Island
Port Island
Rosscorkey Island
Trawnish
Tuam Island

;Lower Lough MacNean

Cushrush Island
Inishee

Cushrush, Inishteig, Kilrooscagh and Rosscorkey are now fayed to the land by small bridges. Cushrush seems to have been dwelt since the Mesolithic period as many microlithic flint tools have been found there.
There are also the remains of two crannogs; one in each lake. These were small manmade islands used as dwellings in ancient times.