In Croatia, Rathmann families are Croats (from Dubrovnik ).
Prevalence
Only a few people with faimily name Rathmann live in Croatia today, in two households only. They are located in two Croatian cities only, in Dubrovnik (<5) and Zagreb (<5).
Outside Croatia
Family name Rathmann is present in 24 countries worldwide. The family name "Rathmann " is used by some 3000 people in Germany , about 900 in the United States , and some 100 people in Denmark.