The founders of the Uí Néill branches are the alleged sons of Niall Noigiallach, seven in all:
The Northern Uí Néill branch:
The Southern Uí Néill branch:
All these men were in their lifetime known as members of Connachta dynasty, or as "the sons of Niall." The term Uí Néill did not, by its very nature, come into use until the time of Niall's grandsons and great-grandsons.
Dynasties descended from the Uí Néill, such as the Cenél Conaill and Cenél nEógain, held power in Ulster until their defeat in the Nine Years War in 1603. Many of the heads of the families left for Catholic Europe in 1607, an event known as the Flight of the Earls.
Bold indicates a supposed High King of Ireland.