Železnjak families are Croats and they are mostly from Cakovec. In the past century, relatively most of Croatian residents bearing this family name were born in Cakovec and in Cakovec area.
Prevalence
About 70 people with faimily name Železnjak live in Croatia today, in 40 households. There were 80 of them in the middle of the past century, and their number decreased by 10 percent. They are located in 7 Croatian counties and 10 other places, mostly in Cakovec (40), and in Nedelisce (15), Orehovica (<10), Vularija (<10) and Gardinovec (<5) in Cakovec area.
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.