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