Radeljak families are Croats and they are mostly from Bosnian Krajina. In the past century, relatively most of Croatian residents bearing this family name were born in Bosnian Krajina (Teslic area) and in Drnis. In Tepljuh in Drnis every fourth inhabitant had the family name Radeljak.
Prevalence
About 210 people with faimily name Radeljak live in Croatia today, in 90 households. There were 100 of them in the middle of the past century, and their number doubled. They are located in the most of Croatian counties, in 24 cities and 24 other places, mostly in Zagreb (45), Drnis (25), Split (15), Siveric (10), and in Djeletovci in Vinkovci area (10).
Outside Croatia
Family name Radeljak is present in 11 countries on four continents. The family name "Radeljak " is used by some 100 people in Argentina and small number in the United States.
In the sources analysed in the project Acta Croatica so far, the name is mentioned over five times, the first time 2007 in source Encyclopaedia of Croatian Surnames.