In Croatia, Riess families are Croats (from Zagreb ).
Prevalence
Only a few people with faimily name Riess live in Croatia today, in one household only. They are located in one Croatian city only, in Zagreb (<5).
Outside Croatia
Family name Riess (including: Rieß , Eriess ) is present in 39 countries worldwide. The family name "Riess " is used by some 4000 people in Germany , about 2000 in the United States , and some 600 people in Austria.
In the sources analysed in the project Acta Croatica so far, the name is mentioned over five times, the first time 1917 in source List of Dignitaries, Officials and Public Servants of the Kingdom of Croatia-Slavonia.