In Croatia, Košković families are Croats (from Hrvatska Kostajnica area ). In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and Sisak.
Prevalence
About 60 people with faimily name Košković live in Croatia today, in 20 households. There were 90 of them in the middle of the past century, and their number decreased by 40 percent. They are located in threee Croatian counties and four other places, mostly in Velika Gorica (25), Sesvete (15), in Zreme (10) and Sunja (<5) in Hrvatska Kostajnica area, and in Zagreb (<5).
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.