Koštić families are often Croats and they are mostly from Imotski area (Studenci), rarely Bosniaks from middle Bosnia. According to some sources they are from Velika Kladusa (Bosnia). In the past century, relatively most of Croatian residents bearing this family name were born in Imotski area and in Cazins Region, Bosnia (Velika Kladusa area). In Vrnograč in Cazins Region (Bosnia) every seventh inhabitant had the family name Koštić.
Prevalence
About 260 people with faimily name Koštić live in Croatia today, in 100 households. There were 90 of them in the middle of the past century, and their number tripled. They are located in the most of Croatian counties, in 16 cities and 14 other places, mostly in Split (70), Zagreb (60), Sisak (25), Ivankovo in Vinkovci area (25), and in Koprivnica (20).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over sixty times, the first time 1917 in source List of Dignitaries, Officials and Public Servants of the Kingdom of Croatia-Slavonia.