Spoja families are Croats and they are mostly from Skradin. In the past century, relatively most of Croatian residents bearing this family name were born in Rijeka and Skradin.
Prevalence
About 70 people with faimily name Spoja live in Croatia today, in 30 households. There were 30 of them in the middle of the past century, and their number more than doubled. They are only located in in 8 Croatian cities and another small place , mostly in Bribir in Novi Vinodolski area (40), Crikvenica (<10), Novi Vinodolski (<10), Zagreb (<5), and in Rijeka (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 2007 in source Encyclopaedia of Croatian Surnames.