Trnski families are Croats and they are mostly from Djurdjevac area. According to some sources they are from Czechia. In the past century, relatively most of Croatian residents bearing this family name were born in Djurdjevac area and in Zagreb.
Prevalence
About 140 people with faimily name Trnski live in Croatia today, in 60 households. There were 160 of them in the middle of the past century, and their number decreased by 10 percent. They are located in 8 Croatian counties, in 11 cities and 14 other places, mostly in Novigrad Podravski in Djurdjevac area (40), Zagreb (30), Bjelovar (20), Koprivnica (10), and in Narta in Cazma area (<10).
Outside Croatia
Family name Trnski is present in 7 countries on three continents.
In the sources analysed in the project Acta Croatica so far, the name is mentioned over thirty times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.