Occupying just over 17% of the island of Ireland, Northern Ireland is certainly crisscrossed by uplands and low mountains, but its most prominent and arguably its most valuable landform is Lough Neagh, the largest freshwater lake in the United Kingdom and one of the largest in western Europe.
As for those mountains, the major ranges include the Sperrin, Mourne, and the (volcanic in origin) Antrim Plateau that stretches along its northeastern coastline. Slieve Donard in the Mourne Mountains of the south is its highest point, rising to 850 meters, (2,782 feet).
The most striking feature of Northern Ireland is the so-called Giant's Causeway on the north Antrim coast. This area of thousands of interlocking basalt columns is the byproduct of an ancient volcanic eruption, with some of the columns reaching 12 meters (36 ft) high.
Two of the largest rivers, the Bann (north and south) and the Foyle, are fronted by fertile lowland areas. Addition rivers of significance in Northern Ireland include the Logan and Mourne.
In the southwest, the Lower and Upper Lough Erne are its second and third largest inland bodies of water.