In Croatia, Radja families are Croats (from Krizevci area ). In the past century, relatively most of Croatian residents bearing this family name were born in Rijeka and in Backa, Vojvodina.
Prevalence
About 20 people with faimily name Radja live in Croatia today, in 8 households. There were 40 of them in the middle of the past century, and their number halved. They are located and two other Croatian places, mostly in Split (15), Zagreb (<5), Rijeka (<5), Sesvete (<5), and in Vinkovci (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.