Lough Neagh is a large freshwater lake in Northern Ireland. It is the largest lake by area in the British Isles, with a surface area of 151 square miles (392 square kilometres). It supplies 40% of Northern Ireland's water. Its main inflows are the Upper River Bann and River Blackwater, and its main outflow is the Lower River Bann. Its name comes from Irish: Loch nEachach, meaning "Eachaidh's lake". The lough is owned by the Earl of Shaftesbury.

With an area of 151 square miles (392 km2), it is the largest lake on the island of Ireland, the 15th largest freshwater lake within the European Union and is ranked 31st in the List of largest lakes of Europe. Located 20 miles (32 km) west of Belfast, it is about 20 miles (32 km) long and 9 miles (14 km) wide. It is very shallow around the margins and the average depth in the main body of the lake is about 30 feet (9 m), although at its deepest the lough is about 80 feet (24 m) deep.

Lower Lough Erne Northern Ireland 42.28 mi² 109.5 km²

Loch Lomond Scotland 27.45 mi² 71 km²

Loch Ness Scotland 21.78 mi² 56 km²

More Info: en.wikipedia.org