Rumenjak families are Croats and they are mostly from Krizevci area. In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and in Krizevci area.
Prevalence
About 160 people with faimily name Rumenjak live in Croatia today, in 70 households. There were 190 of them in the middle of the past century, and their number decreased by 10 percent. They are located in the most of Croatian counties, in 12 cities and 21 other places, mostly in Zagreb (65), Sesvete (15), Rusani in Virovitica area (10), Bjelovar (<10), and in Krizevci (<10).
Outside Croatia
Family name Rumenjak is present in five countries on two continents. "Rumenyak " is used by few 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 2007 in source Encyclopaedia of Croatian Surnames.