Duilo families are Croats and they are mostly from Drnis. In the past century, relatively most of Croatian residents bearing this family name were born in Drnis and Zagreb.
Prevalence
About 150 people with faimily name Duilo live in Croatia today, in 70 households. There were 100 of them in the middle of the past century, and their number increased by 50 percent. They are located in 8 Croatian counties, in 13 cities and 9 other places, mostly in Zagreb (40), Split (30), Sibenik (20), Knin (15), and in Skradin (<10).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 2007 in source Encyclopaedia of Croatian Surnames.