Sergo families are mainly Croats and they are mostly from Buzet area , rarely Italians. In the past century, relatively most of Croatian residents bearing this family name were born in Rijeka and Pula. In Dolenja Vas in Buzet area every fourth inhabitant had the family name Sergo.
Prevalence
About 190 people with faimily name Sergo live in Croatia today, in 80 households. There were 310 of them in the middle of the past century, and their number decreased by 40 percent. They are located in threee Croatian counties, in 9 cities and 32 other places, mostly in Rijeka (35), Pula (20), Opatija (15), Dolenja Vas in Buzet area (10), and in Porec (<10).
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.