Topolnjak families are Croats and they are mostly from Jastrebarsko area. In the past century, relatively most of Croatian residents bearing this family name were born in Cakovec and in Cakovec area.
Prevalence
About 280 people with faimily name Topolnjak live in Croatia today, in 120 households. There were 150 of them in the middle of the past century, and their number increased by 100 percent. They are located in 9 Croatian counties, in 10 cities and 28 other places, mostly in Nedelisce in Cakovec area (70), Cakovec (45), Zagreb (35), Lasinja in Jastrebarsko area (25), and in Varazdin (15).
Outside Croatia
At least four families with this surname emigrated from Croatia to the United States (2) and Australia (2). Family name Topolnjak (including: Topolnyak , Topolniak ) is present in 15 countries worldwide.
In the sources analysed in the project Acta Croatica so far, the name is mentioned over five times, the first time 2007 in source Encyclopaedia of Croatian Surnames.