In Croatia, Cvjak families are Croats (from Srijem, Vojvodina ). In the past century, relatively most of Croatian residents bearing this family name were born in Bosanian Posavina (Derventa area) and in Srijem, Vojvodina.
Prevalence
About 20 people with faimily name Cvjak live in Croatia today, in three households only. They are located in only five naselja i to in Dugo Selo (<10), Sesvetski Kraljevec (<5), Svibje in Dugo Selo area (<5), Zagreb (<5), and in Sesvete (<5).