The Cenel Conaill, Cenel Eogain and Cenel Enna were the three branches of the northern Ui Neill. The Cenel Conaill centered themselves around the area of Magh Ithe, in the valley of the river Finn and controlled the major part of the County from Donegal Bay to the Swilly, the Cenel Eoghain established their power base at Inishowen and their capital at Aileach controlling Inis Eoghain (later spreading into Derry and Tyrone) and the Cenel Enna controlled a smaller strip of land in East Donegal and West Tyrone.

The O’Donnells (Cenel Conaill) and the O’Neills (Cenel Eogain) are said to be the two greatest Ulster dynasties. Their rivalry lasted for over a thousand years.

Map link to Northern Ui Neill Circa 800 A.D.:
http://www.rootsweb.com/~irlkik/ihm/uineill.htm

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Dearg