In Croatia, Castellan families are Croats by relative majority (from the Island of Cres ), equally Italians.
Prevalence
Only a few people with faimily name Castellan live in Croatia today, in one household only. They are located in one Croatian city only, in Cres on the Island of Cres (<5).
Outside Croatia
At least two families with this surname emigrated from Croatia to Canada (1) and the United States (1). Family name Castellan is present in 30 countries worldwide.
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1906 in source Yearbook and Directory of Literary Society of St. Jerome 1906.