Kozjak families are Croats and they are mostly from Cakovec. According to some sources they are from Varazdin. In the past century, relatively most of Croatian residents bearing this family name were born in Cakovec and Zagreb.
Prevalence
About 430 people with faimily name Kozjak live in Croatia today, in 200 households. There were 530 of them in the middle of the past century, and their number decreased by 20 percent. They are located in the most of Croatian counties, in 33 cities and 43 other places, mostly in Zagreb (105), Cakovec (60), Virovitica (25), Cret in Krapina area (25), and in Belica in Cakovec area (20).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over twenty times, the first time 1672 in source Catholic Church Parish Records.