In Croatia, Nikolaus families are almost entirely Croats (from Ogulin ), barely Bosniaks (from Slatina ). In the past century, relatively most of Croatian residents bearing this family name were born in Ogulin and Virovitica.
Prevalence
About 50 people with faimily name Nikolaus live in Croatia today, in 20 households. There were 50 of them in the middle of the past century, and their number remains constant. They are located in 6 Croatian counties, in 7 cities and 5 other places, mostly in Zagreb (<10), Osijek (<10), Vrbovsko (<10), Slatina (<5), and in Knezevo in Beli Manastir area (<5).
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.