In Croatia, Reiz families are Bosniaks by relative majority (from Bosnian Posavina ), equally Croats. In the past century, relatively most of Croatian residents bearing this family name were born in Bosanian Posavina (Derventa area).
Prevalence
Only a few people with faimily name Reiz live in Croatia today, in four households only. They are located in two Croatian cities only, in Rijeka (<5) and Smrika (<5).
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.