In Croatia, Kastner families are Croats (from Daruvar area ). In the past century, relatively most of Croatian residents bearing this family name were born in Daruvar area and in Zagreb.
Prevalence
About 10 people with faimily name Kastner live in Croatia today, in 8 households. There were 30 of them in the middle of the past century, and their number decreased significantly. They are located in 7 Croatian counties, threee cities and four other places, mostly in Zagreb (10), Lipovljani in Novska area (<5), Delnice (<5), Brajkovici in Rovinj area (<5), and in Karlovac (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.