In Croatia, Švrljuga families are almost entirely Croats (from Bakar ), barely Serbs, and . In the past century, relatively most of Croatian residents bearing this family name were born in Rijeka and Zagreb. In Zamost Brodski in Delnice every eighth inhabitant had the family name Švrljuga.
Prevalence
About 60 people with faimily name Švrljuga live in Croatia today, in 30 households. There were 70 of them in the middle of the past century, and their number decreased by 10 percent. They are located in threee Croatian counties, in 7 cities and two other places, mostly in Hreljin (15), Rijeka (15), Zagreb (10), and in Cavle (<10) and Cernik (<10) in Rijeka area.
Outside Croatia
At least six families with this surname emigrated from Croatia to: the United States (4), Canada (1), and to Germany (1). Family name Švrljuga (including: Sverljuga , Svrljuga ) is present in this form only in Croatia.
In the sources analysed in the project Acta Croatica so far, the name is mentioned over thirty times, the first time 1906 in source Yearbook and Directory of Literary Society of St. Jerome 1906.