Kucljak families are Croats and they are mostly from Zlatar area. In the past century, relatively most of Croatian residents bearing this family name were born in Zlatar area and in Virovitica. In places Kosovečko and Klimen in Zlatar area every tenth inhabitant had the family name Kucljak.
Prevalence
About 110 people with faimily name Kucljak live in Croatia today, in 40 households. They are located in the most of Croatian counties, in 10 cities and 16 other places, mostly in Zagreb (20), Brezik in Virovitica area (15), Vinkovci (10), Grtovec in Zlatar area (10), and in Varazdin (<10).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 2007 in source Encyclopaedia of Croatian Surnames.