Kostanjevac families are Croats and they are mostly from Ivanec area. In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and Varazdin. In Marčan in Ivanec area every twentieth inhabitant had the family name Kostanjevac.
Prevalence
About 120 people with faimily name Kostanjevac live in Croatia today, in 50 households. There were 250 of them in the middle of the past century, and their number halved. They are located in 10 Croatian counties, in 12 cities and 15 other places, mostly in Zagreb (30), Varazdin (15), Slatina (10), Dugo Selo (<10), and in Petrijanec in Varazdin area (<10).
Outside Croatia
Family name Kostanjevac is present in two countries.
In the sources analysed in the project Acta Croatica so far, the name is mentioned over five times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.