Kostanić families are Croats and they are mostly from Ploce area. According to some sources they are from Drvenika near Vrgorca. In the past century, relatively most of Croatian residents bearing this family name were born in Makarska and in Ploce area. In Drvenik in Ploce area every sixth inhabitant had the family name Kostanić.
Prevalence
About 120 people with faimily name Kostanić live in Croatia today, in 60 households. There were 100 of them in the middle of the past century, and their number increased by 20 percent. They are only located in in 7 Croatian cities and 5 other places, mostly in Drvenik in Ploce area (70), Zagreb (15), Makarska (15), Ploce (<10), and in Split (<5).
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.