In Croatia, Rozgaj families are Croats (from Ozalj area ). In the past century, relatively most of Croatian residents bearing this family name were born in Ozalj area and in Karlovac. In Sopčić Vrh in Ozalj area every third inhabitant had the family name Rozgaj.
Prevalence
About 10 people with faimily name Rozgaj live in Croatia today, in four households only. There were 20 of them in the middle of the past century, and their number halved. They are located in only threee naselja i to in Sopcic Vrh in Ozalj area (<10), Zagreb (<5), and in Karlovac (<5).
Outside Croatia
Family name Rozgaj is present in four countries on two continents. "Rozgay " 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 few times, the first time 1917 in source List of Dignitaries, Officials and Public Servants of the Kingdom of Croatia-Slavonia.