In Croatia, Korušić families are Croats (from Zabok area ). In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and Cakovec.
Prevalence
About 40 people with faimily name Korušić live in Croatia today, in 19 households. There were 30 of them in the middle of the past century, and their number increased by 10 percent. They are only located in threee Croatian cities and four other places, mostly in Zagreb (<10), Velika Erpenja in Zabok area (<10), Varazdin (<10), Jalsje in Zabok area (<10), and in Cakovec (<5).
Outside Croatia
Family name Korušić is present in this form only in Croatia.
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.