Ó hÁgáin
Ó hÁGÁIN—I—O Hagane, O'Hagan, Hagan, Haggan, &c.; 'descendant of Ógán' (diminutive of óg, young); a northern variant of Ó hÓgáin, which see; the name (1) of a distinguished family of Cinel Eoghain, who were chiefs of Cinel Fearghusa and were seated at Tullaghoge, in Co. Tyrone, where it was O'Hagan's privilege to inaugurate O'Neill; and (2) of another family of the same race who were chiefs of Cinel Tighearnaigh, in Ulster.
Alphabetical Index to Irish Surnames