Eogan, son of Niall Noígiallach, was an Irish king founded the kingdom of Tír Eógan (modern County Tyrone) in the 5th century. He was also the ancestor of the Cenél nEógan dynasty and their septs (O'Neill, O'Docherty, O'Boyle, etc).

Eogan was converted to Christianity and baptized by St. Patrick at the Royal Palace of Aileach, in 442 A.D. He was the King of Aileach, during the 5th century.