Udiljak families are Croats and they are mostly from Imotski area. In the past century, relatively most of Croatian residents bearing this family name were born in Imotski area and in Split.
Prevalence
About 240 people with faimily name Udiljak live in Croatia today, in 90 households. There were 170 of them in the middle of the past century, and their number increased by 40 percent. They are located in 10 Croatian counties, in 18 cities and 12 other places, mostly in Zagreb (85), Split (40), Studenci in Gospic area (35), Studenci in Imotski area (35), and in Stobrec (<10).
Outside Croatia
Family name Udiljak is present in five countries on three continents.
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1906 in source Yearbook and Directory of Literary Society of St. Jerome 1906.