McCullough is an Irish and Scottish surname, with two distinct Gaelic origins: Mac Cú Uladh which means 'son of Cú Uladh' ('Hound of Ulster'). Mac Cullaich 'son of Cullach' ('boar'), usually rendered McCulloch Derivation from the Irish Gaelic Mac Cú Uladh 'son of the hound of Ulster' is more probable. While Cú Uladh may allude to the legendary Irish figure Cú Chulainn, it was a common given name in medieval Ireland. In Ulster it was often in use by the O'Neills of Clandeboye, the MacMahons of O…