Viljac families are Croats and they are mostly from Trogir area. In the past century, relatively most of Croatian residents bearing this family name were born in Trogir area and in Trogir.
Prevalence
About 150 people with faimily name Viljac live in Croatia today, in 60 households. There were 80 of them in the middle of the past century, and their number increased by 90 percent. They are located in four Croatian counties, in 6 cities and 10 other places, mostly in Trogir (55), Zagreb (15), Ljubitovica in Trogir area (15), Sibenik (15), and in Prgomet in Trogir area (15).
Outside Croatia
Family name Viljac is present in 7 countries on three continents. The family name "Viljac " is used by small number of people in the United States and small number in the Netherlands.
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.