Mac Cailín
Mac CAILÍN—IV—M'Calline, MacCallion, MacCallan, MacCallen, [Campbell]; 'son of Cailín' (the Scottish Colin); also Mac Coilín, which see. The family of fighting-men brought over from Scotland by the O'Donnells of Tirconnell in the 15th century, were sometimes called Mac Cailín, sometimes Mac Ailín (which see), and it is impossible to say which form is correct.
Alphabetical Index to Irish Surnames