Dvoržak families are usually Croats and they are mostly from Osijek , rarely Czechs. In the past century, relatively most of Croatian residents bearing this family name were born in Osijek and Zagreb.
Prevalence
About 110 people with faimily name Dvoržak live in Croatia today, in 50 households. There were 150 of them in the middle of the past century, and their number decreased by 20 percent. They are located in the most of Croatian counties, in 19 cities and 12 other places, mostly in Zagreb (30), Osijek (20), Ivanic-Grad (<10), Belisce (<10), and in Novi Majur (<10).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over twenty times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.