Mac Eochagáin
Mac EOCHAGÁIN—IV—M'Keoghegane, M'Coghegan, M'Coogan, Kehigan, MacCogan, Keogan, Coogan, Cooken, Cogan, &c.; 'son of Eochagán' (a diminutive of Eochaidh); a variant of Mag Eochagáin, which see; rare and found only in Cavan and a few other parts of Ulster.
Alphabetical Index to Irish Surnames