Posavac families are Croats and they are mostly from Virovitica area. In the past century, relatively most of Croatian residents bearing this family name were born in Osijek and Virovitica.
Prevalence
About 600 people with faimily name Posavac live in Croatia today, in 280 households. There were 840 of them in the middle of the past century, and their number decreased by 30 percent. They are located in the most of Croatian counties, in 37 cities and 77 other places, mostly in Zagreb (90), Bjelovar (55), Osijek (45), Spisic Bukovica in Virovitica area (45), and in Baranjsko Petrovo Selo in Beli Manastir area (25).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over twenty times, the first time 1749 in source 18th Century Census.