Which lake is the largest by surface area in the United Kingdom?

The largest lake by surface area in the United Kingdom is Lough Neagh in Northern Ireland.

Lough Neagh covers about 383 square kilometres, making it the largest lake in the UK, the island of Ireland, and the British Isles by area. It lies roughly 20 miles west of Belfast and is shared by the shores of five Northern Irish counties.

The lough is relatively shallow compared with its broad surface: its average depth is around 9 metres, while its deepest point is approximately 24 metres. Major inflows include the Upper Bann, Blackwater, River Main, and Six Mile Water; the Lower Bann carries water northward out of the lake.

Loch Ness is a common wrong answer because it is famous and contains more water by volume, despite being much smaller in surface area. Loch Lomond is Scotland’s largest lake by area, while Windermere is England’s largest natural lake. Lough Neagh also supplies a substantial share of Northern Ireland’s drinking water.