Lough Neagh is a freshwater lake in Northern Ireland. The largest lake anywhere in the United Kingdom, the island of Ireland and also the British Isles, with an area of 388 square kilometres (150 square miles), it is also the third largest in Western Europe (after Lake Geneva and Lake Constance). Approximately 30 km (20 mi) long and 15 km (9 mi) wide, Lough Neagh is situated some 30 km (20 mi) to the west of Belfast.

It is very shallow around the margins and the average depth in the main body of the lake is about 9 m (30 ft); although at its deepest the lough is about 25 m (80 ft) deep. 43% of the land area of Northern Ireland is drained into the lough [1], which itself flows out northwards to the sea via the River Bann. As one of its sources is the Upper Bann, the Lough can itself be considered a part of the Bann.

Five of the six counties of Northern Ireland have shores on the Lough: Antrim, Armagh, Down, Londonderry and Tyrone. Towns and villages near the Lough include Antrim, Toomebridge, Ballyronan, Ballinderry, Moortown, Ardboe, Maghery, Lurgan and Magherafelt.

Although the Lough is used for a variety of recreational and commercial activities, it is exposed and tends to get extremely rough very quickly in windy conditions. It is also used as a source of fresh water by the DRD Water Service. Plans to increase the amount of water drawn from the Lough, through a new water treatment works at Hog Park Point, have long been planned but are yet to materialize.

Lough Neagh attracts bird watchers from many nations due to the number and variety of birds which winter and summer in the boglands and shores around the lough.Eel fishing has been a major industry in Lough Neagh for centuries. Today Lough Neagh eel fisheries export their eels to restaurants all over the world.There are a number of islands in the lough: Coney Island, Coney Island Flat, Croaghan Flat, Derrywarragh Island, Padian, Phil Roe's Flat and The Shallow Flat.

Lough Neagh was widely assumed to be owned by the state, but in 2005 it publicly emerged that it is the ancestral property of the Earls of Shaftesbury. This may have serious implications for planned changes to state-run domestic water services in Northern Ireland, as the lough supplies 40% of the region's drinking water and is also used as a sewage outfall (in a system only permissible through Crown immunity).

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