Ardgal Ua Lochlainn was "Lord of Aileach" in 1059. Though thought to have had some connection with the Vikings of Lough Foyle because of the name similarities ("Lochlainn" being the Gaelic for Viking") they were more probably descendants of a Maolsheachlainn Ua Maele-Ruainidh a High-King of Tara formerly Lord of Aileach in the l0th Century and an ancestor of the aforementioned Ardgal.

Lochlann is a corruption of this longer form. The family were indeed Ua Lochlainn originally only becoming McLochlainn in the 13th Century. The O'Loughlins of today have mostly a Co. Clare origin (Lords of the Burren). The "O" form was adopted by a few families of Inishowen (They should, if they wished to be pedantic, call themselves O' Melaghlin, an honourable sept of Co. Meath now rare. They considered themselves descendants of the High-King Malachy, Brian Boru's collaborator).

The McLoughlins were sub-kings to the O'Neills but were ignored when ousted from their Lordship of Inishowen by O'Doherty in the 15th Century. This exclusion was part of a settlement of the mutual claims of the great families, the O'Neills and the O'Donnells over disputed territory in Inishowen and Cinel Maon.