Posavi families are Croats and they are mostly from Ivanec. In the past century, relatively most of Croatian residents bearing this family name were born in Ivanec and Varazdin.
Prevalence
About 110 people with faimily name Posavi live in Croatia today, in 50 households. There were 60 of them in the middle of the past century, and their number increased by 90 percent. They are located in 10 Croatian counties, in 9 cities and 15 other places, mostly in Ivanec (30), Bjelovar (10), Zagreb (<10), Podturen in Mursko Sredisce area (<10), and in Osijek (<10).
Outside Croatia
Family name Posavi is present in four countries on three continents. The family name "Posavi " is used by few people in the United States.
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 2007 in source Encyclopaedia of Croatian Surnames.