Mrzljak families are Croats and they are mostly from Oroslavje. In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and Karlovac. In Dugače in Vrbovsko area every fourth inhabitant had the family name Mrzljak.
Prevalence
About 280 people with faimily name Mrzljak live in Croatia today, in 130 households. There were 410 of them in the middle of the past century, and their number decreased by 30 percent. They are located in the most of Croatian counties, in 21 cities and 29 other places, mostly in Zagreb (105), Oroslavje (35), Tuskani (20), Krusljevo Selo (15), and in Duga Resa (15).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over twenty times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.