In Croatia, Kostric families are predominantly Croats (from Varazdin ), rarely Slovenes (from Slovenia ). In the past century, relatively most of Croatian residents bearing this family name were born in Varazdin and in Slovenia.
Prevalence
Only a few people with faimily name Kostric live in Croatia today, in two households only. There were 0 of them in the middle of the past century, and their number remains constant. They are located in one Croatian city only, in Varazdin (<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.