Postružin families are Croats and they are mostly from Zabok area. In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and Klanjec.
Prevalence
About 220 people with faimily name Postružin live in Croatia today, in 90 households. There were 200 of them in the middle of the past century, and their number increased by 10 percent. They are located in 9 Croatian counties, in 15 cities and 25 other places, mostly in Zagreb (80), Strmec in Zabok area (20), Ivanic-Grad (<10), Tomasevec (<10), and in Zapresic (<10).
Outside Croatia
Family name Postružin is present in this form only in Croatia.
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.