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