Kostanjčar families are Croats and they are mostly from Zapresic area. In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and in Zapresic area.
Prevalence
About 120 people with faimily name Kostanjčar live in Croatia today, in 50 households. There were 90 of them in the middle of the past century, and their number increased by 30 percent. They are located in 7 Croatian counties, in 10 cities and 8 other places, mostly in Jakovlje in Zapresic area (35), Zagreb (30), Privlaka (10), Rijeka (10), and in Bukovec Zelinski (<10).
Outside Croatia
Family name Kostanjčar is present in two countries on two continents. The family name "Kostanjcar " is used by few people in the United States.
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.