Borošak families are Croats and they are mostly from Zabok area. In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and in Zabok area.
Prevalence
About 350 people with faimily name Borošak live in Croatia today, in 140 households. There were 360 of them in the middle of the past century, and their number remains constant. They are located in 9 Croatian counties, in 11 cities and 31 other places, mostly in Zagreb (145), Radakovo in Zabok area (55), Selno in Krapina area (25), Zapresic (15), and in Klanjec (15).
Outside Croatia
Family name Borošak (including: Borosak , Boroschak and Borosac ) is present in five countries on two continents. The family name "Borosak " is used by some 60 people in the United States.
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.