In Croatia, Supanc families are Croats (from Lipik ). In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and Osijek.
Prevalence
About 30 people with faimily name Supanc live in Croatia today, in 10 households. There were 50 of them in the middle of the past century, and their number decreased by 50 percent. They are located in four Croatian counties and another small place , mostly in Zagreb (20), Samobor (<5), Filipovac (<5), Rovinj (<5), and in Pula (<5).
Outside Croatia
Family name Supanc (including: Suppanz , Supanz ) is present in 8 countries on three continents. The family name "Supanc " is used by few people in the United States. "Suppanz " is used by small number of people in Germany , small number in Austria , and small number of people in the United States.
In the sources analysed in the project Acta Croatica so far, the name is mentioned over five times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.