In Croatia, Kastmiler families are generally Croats (from Nova Gradiska area ), very rarely Serbs, and . In the past century, relatively most of Croatian residents bearing this family name were born in Nova Gradiska area and in Sisak. In Novi Varoš in Nova Gradiska area every ninth inhabitant had the family name Kastmiler.
Prevalence
About 40 people with faimily name Kastmiler live in Croatia today, in 17 households. There were 40 of them in the middle of the past century, and their number remains constant. They are located in four Croatian counties and four other places, mostly in Novi Varos in Nova Gradiska area (<10), Sisak (<10), Rijeka (<10), Petrinja (<10), and in Zagreb (<5).
Outside Croatia
Family name Kastmiler is present in three countries on two continents.
