Ó Léanacháin
Ó LÉANACHÁIN—I—O Lenaghan, O Leneghan, Lenaghan, Leneghan, Lenahan, Lenehan, Lenihan, Lennihan, &c.; 'descendant of Léanachán' (diminutive of leannach or léanach, mantled, cloaked); the name of a Roscommon family; still numerous, but dispersed through Connacht; sometimes pronounced Ó Líonacháin.
Alphabetical Index to Irish Surnames