Košić families are Croats and they are mostly from Varazdin area. In the past century, relatively most of Croatian residents bearing this family name were born in Varazdin and Zagreb. In places Nova Ves Petrijanečka and Krkanec in Varazdin area every seventh inhabitant had the family name Košić.
Prevalence
About 360 people with faimily name Košić live in Croatia today, in 140 households. There were 260 of them in the middle of the past century, and their number increased by 40 percent. They are located in the most of Croatian counties, in 18 cities and 30 other places, mostly in Varazdin (50), Persaves in Zlatar area (25), Vidovec in Varazdin area (20), Ivanic-Grad (20), and in Krkanec in Varazdin area (20).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over thirty times, the first time 1749 in source 18th Century Census.