Ó hUallacháin
Ó hUALLACHÁIN—I—O Huolighane, O Holeghane, O Holohan, O'Houlihan, Houlihan, Hoolihan, Holohan, (Holland, Nolan), &c.; 'descendant of Uallachán' (diminutive of uallach, proud); the name of several distinct families, the best known being those of Offaly and Thomond. The name was also very common in West Cork, where it is now often anglicised Holland; also common in Mayo and Roscommon, where it is anglicised Nolan. See Ó Nuallacháin.
Alphabetical Index to Irish Surnames