Šušak families are predominantly Croats and they are mostly from north Herzegovina , less frequently Serbs. In the past century, relatively most of Croatian residents bearing this family name were born in Bosanian Posavina (Bosanski Samac area) and in North Herzegovina (Konjic area). In Mokro in North Herzegovina every eighth inhabitant had the family name Šušak.
About 710 people with faimily name Šušak live in Croatia today, in 320 households. There were 220 of them in the middle of the past century, and their number tripled. They are located in almost all Croatian counties, in 42 cities and 59 other places, mostly in Zagreb (200), Split (80), Sesvete (30), Osijek (25), and in Rijeka (20).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over twenty times, the first time 1917 in source List of Dignitaries, Officials and Public Servants of the Kingdom of Croatia-Slavonia.