Željeznjak families are Croats and they are mostly from Ozalj area. In the past century, relatively most of Croatian residents bearing this family name were born in Karlovac and Varazdin.
Prevalence
About 90 people with faimily name Željeznjak live in Croatia today, in 40 households. There were 80 of them in the middle of the past century, and their number increased by 20 percent. They are located in 8 Croatian counties, in 11 cities and 18 other places, mostly in Karlovac (25), Zagreb (10), Rijeka (<10), Kalinovac in Djurdjevac area (<10), and in Veselici in Ozalj area (<10).
Outside Croatia
Family name Željeznjak is present in this form only in Croatia.
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.