In Croatia, Kosac families are Croats (from Pozega area ). In the past century, relatively most of Croatian residents bearing this family name were born in Pozega and in Pozega area.
Prevalence
About 10 people with faimily name Kosac live in Croatia today, in five households only. There were 30 of them in the middle of the past century, and their number decreased significantly. They are located in only five naselja i to in Daranovci in Pozega area (<10), Pozega (<5), Donji Emovci (<5), Zagreb (<5), and in Brestovac in Pozega area (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 1917 in source List of Dignitaries, Officials and Public Servants of the Kingdom of Croatia-Slavonia.