Bortek families are Croats and they are mostly from Novi Marof area. In the past century, relatively most of Croatian residents bearing this family name were born in Novi Marof area and in Zagreb. In Butkovec in Novi Marof area every fifth inhabitant had the family name Bortek.
Prevalence
About 80 people with faimily name Bortek live in Croatia today, in 40 households. There were 80 of them in the middle of the past century, and their number remains constant. They are located in 8 Croatian counties, in 8 cities and 11 other places, mostly in Zagreb (35), Butkovec in Novi Marof area (10), Cepin in Osijek area (<10), Nasice (<5), and in Veliko Polje (<5).
Outside Croatia
Family name Bortek is present in 8 countries on three continents. "Borteck " is used by small number of people in Thailand and small number in the United States.
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.