The Grianán of Aileach is a hill top fort located on the western edge of a small group of hills. Situated on Greenan Mountain at Inishowen, County Donegal in Ireland that lie between the upper reaches of Lough Swilley and Lough Foyle. A short drive of about 25 minutes from Finn Valley Cottages.
Grianan at sunset
Although the hill not very high (244metres), the summit dominates the neighbouring counties of Londonderry, (Derry), Donegal and Tyrone. Located at the edge of the Inishowen peninsula, it is 11.25 kilometres (7 mi) northwest of the ecclesiastical site of Derry. The views from the carpark and from the fort are spectacular. A wheelchair friendly path links the car park to the fort.
It is believed that the currently existing hillfort was built by Northern Ui Neill around the sixth or seventh century AD, but the first settlement, also a fortress, was most probably created around the 1st century.
The round fort is built largely without mortar. The interior has three terraces which are linked by steps. The wall is about 4.5 metres (15 ft) thick and 5 metres (16 ft) high, with two long passages within it. Originally, there would have been wooden structures were built against the terraces to provide accommodation. Just outside it are the remains of a well and a tumulus. The outline of Bronze Age or Iron Age ramparts can be seen below the fort. Legend states that the giants of Inishowen are lying sleeping but when the sacred sword is removed they will spring to life reclaiming their ancient lands.
It has been identified as the seat of the Kingdom of Ailech and one of the royal sites of Gaelic Ireland. There is much legend and historical material related to the Grianán of Aileach. The Irish Annals record its destruction in 1101. The main monument on the hill is a stone cashel, restored in the nineteenth century, but probably built in the eighth century CE. The summit’s use as an area of settlement may go back much further. A tumulus at the Grianán may date back to the Neolithic age. A covered well was found near the cashel in the early nineteenth century.