Guštin families are almost entirely Croats and they are mostly from Ozalj. According to some sources they are from Gustin near Pazin (Istria), rarely Slovenes. In the past century, relatively most of Croatian residents bearing this family name were born in Ozalj and Karlovac. In Vrškovac in Ozalj every third inhabitant had the family name Guštin.
Prevalence
About 310 people with faimily name Guštin live in Croatia today, in 130 households. There were 400 of them in the middle of the past century, and their number decreased by 20 percent. They are located in the most of Croatian counties, in 20 cities and 29 other places, mostly in Vivodina (50), Zagreb (50), Pazin (30), Pula (15), and in Karlovac (15).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.