In Croatia, Mrdja families are Croats by relative majority (from Ogulin area ), equally Serbs. In the past century, relatively most of Croatian residents bearing this family name were born in Vinkovci and in Bosnian Krajina (Prijedor area).
Prevalence
Only a few people with faimily name Mrdja live in Croatia today, in three households only. They are located in only five Croatian places: in Zagreb (<5), Donji Lapac in Obrovac area (<5), Tordinci in Vinkovci area (<5), and in Birovaca (<5) and Visuc (<5) in Obrovac area.
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.