In Croatia, Šupek families are generally Croats (from Rijeka area ), very rarely Bosniaks (from Zagreb ), and barely Serbs. In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and in Rijeka area.
Prevalence
About 50 people with faimily name Šupek live in Croatia today, in 20 households. There were 30 of them in the middle of the past century, and their number increased by 60 percent. They are located in four Croatian counties and two other places, mostly in Zagreb (40), Cavle in Rijeka area (<10), Sesvete (<5), Rijeka (<5), and in Ivanic-Grad (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.