Oblak families are usually Croats and they are mostly from Delnice area , rarely Slovenes. In the past century, relatively most of Croatian residents bearing this family name were born in Rijeka and in Delnice area.
Prevalence
About 120 people with faimily name Oblak 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 19 other places, mostly in Zagreb (20), Pozega (15), Ravna Gora in Delnice area (15), Rijeka (<10), and in Matulji in Opatija area (<10).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.