In Croatia, Ryšlavy families are generally Croats (from Porec ), rarely Italians (from Pula ).
Prevalence
About 10 people with faimily name Ryšlavy live in Croatia today, in four households only. There were 10 of them in the middle of the past century, and their number remains constant. They are located in three Croatian cities only: in Dracevac (<5), Pula (<5), and in Zagreb (<5).
Outside Croatia
Family name Ryšlavy is present in four countries on two continents. The family name "Ryslavy " is used by small number of people in Germany 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 1906 in source Yearbook and Directory of Literary Society of St. Jerome 1906.