Kosi families are Croats and they are mostly from Cakovec area. In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and Virovitica.
Prevalence
About 140 people with faimily name Kosi live in Croatia today, in 60 households. There were 120 of them in the middle of the past century, and their number increased by 20 percent. They are located in the most of Croatian counties, in 15 cities and 23 other places, mostly in Zagreb (30), Velika Gorica (10), Spisic Bukovica in Virovitica area (10), Sesvete (<10), and in Cabuna in Virovitica area (<10).
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.