Using graphic elements like this world map, to see in which countries or regions of the world the surname O' loughlin is more common, is of great help.
The quantity of people with the surname O' loughlin that we can find in each country can help us discern the origin of the surname O' loughlin, as logic tells us that the place with the most people surnamed O' loughlin will be the country or area of origin of the surname O' loughlin.