In Croatia, Plank families are Croats (from Zupanja ). In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and Karlovac.
Prevalence
About 20 people with faimily name Plank live in Croatia today, in five households only. There were 10 of them in the middle of the past century, and their number doubled. They are located in four Croatian cities only: in Velika Gorica (<10), Mala Mlaka (<5), Zupanja (<5), and in Nova Gradiska (<5).