Polonijo families are Croats and they are mostly from the Island of Krk. In the past century, relatively most of Croatian residents bearing this family name were born in Rijeka and Zagreb.
Prevalence
About 180 people with faimily name Polonijo live in Croatia today, in 80 households. There were 140 of them in the middle of the past century, and their number increased by 40 percent. They are located in 6 Croatian counties, in 14 cities and 10 other places, mostly in Vrbnik on the Island of Krk (60), Rijeka (35), Zagreb (20), and in Jurandvor (15) and Punat (10) on the Island of Krk.
Outside Croatia
At least three families with this surname emigrated from Croatia to the United States (2) and Canada (1). Family name Polonijo is present in three countries on two continents.
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 2007 in source Encyclopaedia of Croatian Surnames.