Osterman families are Croats and they are mostly from Ivanec area. In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and in Ivanec area.
Prevalence
About 70 people with faimily name Osterman live in Croatia today, in 30 households. There were 120 of them in the middle of the past century, and their number decreased by 40 percent. They are located in 10 Croatian counties, in 12 cities and 12 other places, mostly in Zagreb (15), in Vinica (<10) and Cerje Nebojse (<10) in Ivanec area, Virovitica (<10), and in Donje Mekusje (<10).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over five times, the first time 1917 in source List of Dignitaries, Officials and Public Servants of the Kingdom of Croatia-Slavonia.