Petrinjak families are Croats and they are mostly from Novi Marof area. In the past century, relatively most of Croatian residents bearing this family name were born in Varazdin and Zagreb. In Vrh Visočki in Novi Marof area every third inhabitant had the family name Petrinjak.
Prevalence
About 280 people with faimily name Petrinjak live in Croatia today, in 120 households. There were 330 of them in the middle of the past century, and their number decreased by 10 percent. They are located in the most of Croatian counties, in 22 cities and 34 other places, mostly in Ivanec (55), Zagreb (50), Sracinec in Varazdin area (25), Vrh Visocki in Novi Marof area (20), and in Gornja Voca in Ivanec area (15).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.