Kocmanić families are Croats and they are mostly from Glina. In the past century, relatively most of Croatian residents bearing this family name were born in Glina and Sisak. In Ilovačak in Glina every fifth inhabitant had the family name Kocmanić.
Prevalence
About 80 people with faimily name Kocmanić live in Croatia today, in 30 households. There were 100 of them in the middle of the past century, and their number decreased by 20 percent. They are located in 7 Croatian counties, in 7 cities and 10 other places, mostly in Sisak (20), Ilovacak (15), Duzica in Petrinja area (10), Jagodnjak in Beli Manastir area (<10), and in Odra Sisacka (<10).
Outside Croatia
Family name Kocmanić 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 2007 in source Encyclopaedia of Croatian Surnames.