In Croatia, Trdin families are Croats (from Ozalj ). In the past century, relatively most of Croatian residents bearing this family name were born in Osijek and Ozalj.
Prevalence
About 20 people with faimily name Trdin live in Croatia today, in 8 households. There were 20 of them in the middle of the past century, and their number remains constant. They are located in only four naselja i to in Osijek (15), Vrhovac (<10), Mali Erjavec (<5), and in Zajacko Selo (<5).