In Croatia, Brnjak families are almost entirely Croats (from Sveti Ivan Zelina area ), barely Bosniaks. In the past century, relatively most of Croatian residents bearing this family name were born in Middle Bosnia (Jajce area) and in Zagreb.
Prevalence
About 60 people with faimily name Brnjak live in Croatia today, in 20 households. There were 40 of them in the middle of the past century, and their number increased by 50 percent. They are located in 8 Croatian counties and 13 other places, mostly in Zagreb (15), Omamno in Sveti Ivan Zelina area (10), Markovac Nasicki (<10), and in Djurdjenovac (<5) and Podgorac (<5) in Nasice 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.