In Croatia, Jacek families are Croats (from Djakovo ). In the past century, relatively most of Croatian residents bearing this family name were born in Djakovo and Osijek.
Prevalence
About 10 people with faimily name Jacek live in Croatia today, in three households only. There were 10 of them in the middle of the past century, and their number remains constant. They are located in two Croatian cities only, in Djakovo (10) and Treglava (<5).