In Croatia, Blek families are Croats (from Middle Bosnia ). In the past century, relatively most of Croatian residents bearing this family name were born in Middle Bosnia (Zepce area) and in Middle Bosnia (Zavidovici area). In Ravne Gornje in Middle Bosnia every ninth inhabitant had the family name Blek.
Prevalence
About 30 people with faimily name Blek live in Croatia today, in 12 households. They are located in 6 Croatian counties and 6 other places, mostly in Sesvete (<10), Donje Podotocje (<10), Prnjavor in Slavonski Brod area (<10), Loviste on the Peljesac peninsula (<10), and in Mali Losinj on the Island of Losinj (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.