The Grianan of Aileach (Grianán Ailigh) is a hill fort which is over 23 meters in diameter with surrounding earthworks and sits on top of Greenan Hill, 250m above sea level.
The fort dates back to around 1700 BC, it is linked to the Tuatha de Danann who invaded Ireland before the Celts and built stone forts on top of strategic hills. Close to the monument, there is a Well which it is said was blessed by St Patrick.
Some of the myths and legends of Tuatha de Danann can be found in the Old Church Visitor Centre at the An Grianán Hotel at the bottom of the hill. There is also the iconic St. Aengus Church
From the fort, you have spectacular views over Donegal and Lough Swilly as well as Lough Foyle and Derry and even as far as County Tyrone.
To see a 3d model of Grianan of Aileach and to read more about the fort click here.