The Clan/Sept History

This name is derived from the Irish and the Scottish Mac Lochlainn, from the personal name Loch meaning lake and Lann meaning 'land'. The name MacLoughlin is most common in Connacht and Leinster while the name McLaughlin is most common in Ulster, particularly in Antrim, Donegal and Derry.

There are many Irish surnames being used today in forms that are quite different
than their original, ancient forms. MacLoughlin originally appeared in Gaelic as
Mac Lochlainn or O Maoilsheachlainn. The first name is derived from a Norse
personal name, while the second name originally designated a follower of St.
Secundinus.

Spelling variations of this family name include: MacLoughlin, McLoughlin,
MacGloughlin, Lochlain and others.
First found in county Meath, where they held a family seat from very ancient
times, long before the Norman Conquest of England in 1066 A.D.
Some of the first settlers of this family name or some of its variants were:
Thomas, Bridget, Catherine and Helen MacLoughlin who settled in Quebec in 1849;
Bernard, Charles, Denis, Hugh, James, John, Michael, Patrick, Thomas and William
MacLoughlin all arrived in Philadelphia between 1823 and 1860. The family also
settled in Newfoundland between 1792 and 1872..