Vlainić families are almost entirely Croats and they are mostly from Nova Gradiska area , rarely Serbs. In the past century, relatively most of Croatian residents bearing this family name were born in Nova Gradiska area and in Nova Gradiska. In Godinjak in Nova Gradiska area every seventh inhabitant had the family name Vlainić.
Prevalence
About 400 people with faimily name Vlainić live in Croatia today, in 160 households. There were 340 of them in the middle of the past century, and their number increased by 20 percent. They are located in almost all Croatian counties, in 28 cities and 29 other places, mostly in Godinjak in Nova Gradiska area (75), Zagreb (50), Osijek (30), Cernik in Nova Gradiska area (25), and in Nova Gradiska (20).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over thirty times, the first time 1906 in source Yearbook and Directory of Literary Society of St. Jerome 1906.