Bertoša families are almost entirely 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 Pula and Pazin. In Kaldir in Buzet area every sixth inhabitant had the family name Bertoša.
Prevalence
About 190 people with faimily name Bertoša live in Croatia today, in 70 households. There were 150 of them in the middle of the past century, and their number increased by 20 percent. They are only located in in 12 Croatian cities and 18 other places, mostly in Pazin (30), Kaldir in Buzet area (15), Labin (10), and in Karojba (<10) and Novaki Motovunski (<10) in Pazin area.
In the sources analysed in the project Acta Croatica so far, the name is mentioned over five times, the first time 1906 in source Yearbook and Directory of Literary Society of St. Jerome 1906.