Thanks to this world map that shows the density of people with the surname Mortagh in different countries, you can get an idea not only of the popularity of the surname Mortagh in each country but also of the different migrations of people surnamed Mortagh.
The quantity of people with the surname Mortagh that we can find in each country can help us discern the origin of the surname Mortagh, as logic tells us that the place with the most people surnamed Mortagh will be the country or area of origin of the surname Mortagh.