In Croatia, Trnka families are generally Croats (from Nova Gradiska area ), very rarely Czechs (from Grubisno Polje ). In the past century, relatively most of Croatian residents bearing this family name were born in Nova Gradiska and Zagreb.
Prevalence
About 50 people with faimily name Trnka live in Croatia today, in 20 households. There were 50 of them in the middle of the past century, and their number remains constant. They are located in 8 Croatian counties, in 9 cities and 6 other places, mostly in Zagreb (15), Dragalic in Nova Gradiska area (10), Nova Gradiska (<10), Bjelovar (<10), and in Rijeka (<10).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.