In Croatia, Kusmuk families are Serbs. In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and in North Herzegovina (Konjic area).
Prevalence
Only a few people with faimily name Kusmuk live in Croatia today, in one household only. They are located in one Croatian city only, in Zagreb (<5).
Outside Croatia
Family name Kusmuk is present in 10 countries on four continents. The family name "Kusmuk " is used by small number of people in Germany , small number of people in the United States , and small number of people in Australia.