Lake Lough Neagh

Lake Lough Neagh, a prominent freshwater lake located in Northern Ireland, is distinguished as the largest lake both on the island of Ireland and within the United Kingdom. Encompassing a vast area of 151 square miles (392 square kilometers), the lake extends approximately 19 miles (31 km) in length and 9 miles (14 km) in width. Its significant role is underscored by its contribution to the region’s water supply, accounting for 40.7% of Northern Ireland’s drinking water.

The lake’s primary water sources include the Upper River Bann and the Blackwater River, while its main outflow is the Lower Bann. Lough Neagh is dotted with several small islands such as Ram’s Island, Coney Island, and Derrywarragh Island, adding to its geographic diversity. The lake bed is under the ownership of the 12th Earl of Shaftesbury, and its management is overseen by the Lough Neagh Partnership. The name of the lake, derived from the Irish “Loch nEachach,” translates to “Eachaidh’s lake.”

Geographically, Lough Neagh holds the title of being the largest lake in the British Isles by area and ranks 33rd among Europe’s largest lakes. Positioned approximately 20 miles west of Belfast, the lake is characterized by its shallow margins, with an average depth of around 30 feet in the main body, reaching up to about 80 feet at its deepest point.

From a geological perspective, the Lough Neagh Basin is a product of multiple tectonic events dating back as far as 400 million years. These events have shaped the NE-SW bedrock structure, influencing the lake’s formation and subsequent developments. The basin itself emerged as a depositional graben during the Paleozoic era.

In terms of hydrology, the lake’s vast catchment area of 1,760 square miles is predominantly located within Northern Ireland, accounting for about 91%, with the remaining 9% in the Republic of Ireland. This catchment area comprises approximately 43% of Northern Ireland’s land area. The lake is fed by several rivers, including the Main, Six Mile Water, Upper Bann, Blackwater, Ballinderry, and Moyola, making it a crucial component of the region’s river system. As a source of the Upper Bann, Lough Neagh is an integral part of the Bann’s watershed. The lake’s unique geographical, geological, and hydrological characteristics make it a key natural feature in the British Isles.