In Croatia, Supek families are generally Croats (from Ilok ), very rarely Bosniaks (from Zagreb ), and . In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and Ilok.
Prevalence
About 40 people with faimily name Supek live in Croatia today, in 17 households. There were 40 of them in the middle of the past century, and their number remains constant. They are located and four other Croatian places, mostly in Zagreb (20), Ilok (15), Vukovar (<5), Zminj in Pazin area (<5), and in Velika Gorica (<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.