In Croatia, Spretnjak families are Croats (from Jastrebarsko ). In the past century, relatively most of Croatian residents bearing this family name were born in Jastrebarsko and Zagreb. In Petrovina in Jastrebarsko every ninth inhabitant had the family name Spretnjak.
Prevalence
About 30 people with faimily name Spretnjak live in Croatia today, in 10 households. There were 40 of them in the middle of the past century, and their number decreased by 30 percent. They are located in only threee naselja i to in Petrovina (20), Zagreb (<10), and in Jastrebarsko (<5).
Outside Croatia
At least two families with this surname emigrated from Croatia to the United States. Family name Spretnjak is present in two countries on two continents. The family name "Spretnjak " is used by small number of people in the United States.
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 1906 in source Yearbook and Directory of Literary Society of St. Jerome 1906.