In Croatia, Coljak families are Croats (from Sveti Ivan Zelina ). In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and in Novi Marof area.
Prevalence
About 20 people with faimily name Coljak live in Croatia today, in 10 households. There were 30 of them in the middle of the past century, and their number decreased by 10 percent. They are located in only four Croatian places: in Zagreb (10), Sesvete (<5), Novo Mjesto (<5), and in Zamladinec in Krizevci area (<5).