In Croatia, Kalak families are generally Croats (from Sisak ), very rarely Serbs. In the past century, relatively most of Croatian residents bearing this family name were born in Sisak and in Bosanian Posavina (Derventa area).
Prevalence
About 20 people with faimily name Kalak live in Croatia today, in four households only. They are located in one Croatian city only, in Sisak (20).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1906 in source Yearbook and Directory of Literary Society of St. Jerome 1906.