In Croatia, Trefilj families are Croats (from Ivanic-Grad ). In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and in Novi Marof area.
Prevalence
Only a few people with faimily name Trefilj live in Croatia today, in one household only. They are located in two Croatian cities only, in Ivanic-Grad (<10) and Zagreb (<5).
Outside Croatia
Family name Trefilj (including: Trefeli , Trefely ) is present in three countries on two continents.