Koić families are Croats and they are mostly from the Island of Pasman. In the past century, relatively most of Croatian residents bearing this family name were born on the Island of Pasman and in Zagreb.
Prevalence
About 200 people with faimily name Koić live in Croatia today, in 100 households. There were 10 of them in the middle of the past century, and their number multiplied. They are located in the most of Croatian counties, in 15 cities and 13 other places, mostly in Zagreb (60), Starigrad on the Island of Pasman (35), Osijek (20), Cacinci in Orahovica area (15), and in Zadar (15).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1925 in source Emigration Commission Zagreb.