Filjak families are Croats and they are mostly from Djurdjevac area. In the past century, relatively most of Croatian residents bearing this family name were born in Djurdjevac area and in Nasice area.
Prevalence
About 150 people with faimily name Filjak live in Croatia today, in 70 households. There were 180 of them in the middle of the past century, and their number decreased by 20 percent. They are located in 9 Croatian counties, in 12 cities and 14 other places, mostly in Pitomaca in Djurdjevac area (50), Zagreb (25), Kladare in Djurdjevac area (20), Djurdjenovac in Nasice area (15), and in Rijeka (<10).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over five times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.