Vuljak families are Croats and they are mostly from Koprivnica area. In the past century, relatively most of Croatian residents bearing this family name were born in Koprivnica area and in Koprivnica.
Prevalence
About 120 people with faimily name Vuljak live in Croatia today, in 50 households. There were 200 of them in the middle of the past century, and their number decreased by 40 percent. They are located in 7 Croatian counties, in 9 cities and 12 other places, mostly in Djelekovec in Koprivnica area (40), Koprivnica (35), Novigrad Podravski in Djurdjevac area (10), Drnje in Koprivnica area (<10), and in Zagreb (<5).
Outside Croatia
At least one family with this surname emigrated from Croatia to the United States. Family name Vuljak is present in four countries on two continents. The family name "Vuljak " is used by few people in the United States. "Vulyak " is used by small number of people in the United States.
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.