In Croatia, Maslek families are mainly Croats (from Peljesac Peninsula ), equally Serbs. In the past century, relatively most of Croatian residents bearing this family name were born in Karlovac and Bjelovar. In Donji Sjeničak in Karlovac every eighth inhabitant had the family name Maslek.
Prevalence
About 50 people with faimily name Maslek live in Croatia today, in 30 households. There were 100 of them in the middle of the past century, and their number halved. They are only located in in 8 Croatian cities and four other places, mostly in Zagreb (10), Veliko Korenovo (<10), Donji Sjenicak (<10), Karlovac (<10), and in Gornji Draganec (<5).
Outside Croatia
At least one family with this surname emigrated from Croatia to the United States. Family name Maslek (including: Masleck , Maslechah ) is present in 11 countries worldwide. The family name "Maslek " is used by some 50 people in Poland , small number in France , and small number of people in the United States.
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 1917 in source List of Dignitaries, Officials and Public Servants of the Kingdom of Croatia-Slavonia.