Opačak families are Croats and they are mostly from Bosnian Posavina. According to some sources they are from Vrgorac, or from Citluk area (Herzegovina). In the past century, relatively most of Croatian residents bearing this family name were born in Bosanian Posavina (Derventa area) and in Slavonski Brod. In places Žeravac and Donja Vrela in Bosanian Posavina every eighth inhabitant had the family name Opačak.
Prevalence
About 1200 people with faimily name Opačak live in Croatia today, in 470 households. There were 150 of them in the middle of the past century, and their number multiplied. They are located in almost all Croatian counties, in 53 cities and 84 other places, mostly in Slavonski Brod (470), Zagreb (145), Osijek (70), Makarska (45), and in Trogir (30).
Outside Croatia
Family name Opačak (including: Opacak , Opachak ) is present in 18 countries on four continents.
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.