Kuprešak families are mainly Croats and they are mostly from Bosnian Posavina , barely Serbs. In the past century, relatively most of Croatian residents bearing this family name were born in Bosanian Posavina (Derventa area) and in Doboj, Bosnia (Doboj area).
Prevalence
About 430 people with faimily name Kuprešak live in Croatia today, in 170 households. There were 10 of them in the middle of the past century, and their number multiplied. They are located in almost all Croatian counties, in 32 cities and 56 other places, mostly in Zagreb (60), Sesvete (30), Zupanja (30), Slavonski Brod (30), and in Dugo Selo (25).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 2007 in source Encyclopaedia of Croatian Surnames.