In Croatia, Košturić families are Croats (from Duga Resa ). In the past century, relatively most of Croatian residents bearing this family name were born in Duga Resa and Karlovac.
Prevalence
About 20 people with faimily name Košturić live in Croatia today, in 6 households. There were 40 of them in the middle of the past century, and their number halved. They are located in two Croatian cities only, in Mreznicki Novaki (<10) and Karlovac (<10).