Ó hArrachtáin
Ó hARRACHTÁIN—I—O Haraghtane, O Harreghtane, O Harrighton, O Herraghton, Harroughton, Haroughton, (Harrington, Errington, Irrington), &c.; 'descendant of Arrachtán' (diminutive of arrachta, tall, mighty, brave, heroic); the name of a family of Ui Maine in Co. Galway. In the 16th century, it was scattered through all North Munster. To be distinguished from Ó hIongardail and Ó hOireachtaigh, which are also anglicised Harrington.
Alphabetical Index to Irish Surnames