Ó Cathaláin
Ó CATHALÁIN—I—O Cahallane, O Cohallan, Cahallane, Cahillane, Cahalane, Cohalane, Cohalan, Callan, Culhane, Clahane, Clehane, &c.; 'descendant of Cathalán' (diminutive of Cathal, battle-mighty); also written Ó Cathláin, which see; the name (1) of a Roscommon family who were formerly chiefs of Clann Fogartaigh; (2) of a Limerick family, formerly chiefs of Uaitne Cliach, now the barony of Owneybeg, until dispossessed by the O'Mulryans; (3) of an Ulster family, now represented by Callan in Monaghan and Louth; and, doubtless, of other families in different parts of Ireland. All the above-mentioned families were well represented in the 16th century; and the name was then also in Offaly, Leix, Kildare, Cork and Kerry.
Alphabetical Index to Irish Surnames