The Mourne Mountains were formed 65 million years ago. They are made of granite which is an igneous rock. Granite is a hard wearing rock which is found at the base or bottom of the earth's crust. It cools, solidifies and then becomes granite.
There are 12 peaks over 2000 feet high, including Northern Ireland's highest mountain, Slieve Donard. The Mournes are unusual in that their summits are grouped together in a compact area only 7 miles in breadth.
The Mourne Mountains - Famous the world over through Percy French's song "Where the Mountains of Mourne sweep down to the sea".