Jačmenjak 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 Varazdin.
Prevalence
About 70 people with faimily name Jačmenjak live in Croatia today, in 30 households. There were 100 of them in the middle of the past century, and their number decreased by 30 percent. They are only located in four Croatian cities and 10 other places, mostly in Krizevci (20), Zagreb (15), and in Kostanjevec Rijecki (15), Gornja Rijeka (<10) and Vrh Visocki (<5) in Novi Marof area.
Outside Croatia
Family name Jačmenjak is present in two countries on two continents.
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.