Tonšić families are Croats and they are mostly from the Island of Brac. In the past century, relatively most of Croatian residents bearing this family name were born on the Island of Brac and in Split.
Prevalence
About 80 people with faimily name Tonšić live in Croatia today, in 40 households. There were 80 of them in the middle of the past century, and their number remains constant. They are located in four Croatian counties, in 8 cities and four other places, mostly in Selca (20) and Sutivan (15) on the Island of Brac, Split (10), Barbat na Rabu on the Island of Rab (<10), and in Zagreb (<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.