In Croatia, Allen families are Croats (from Split ).
Prevalence
Only a few people with faimily name Allen live in Croatia today, in one household only. They are located in threee Croatian counties, threee cities and another small place , mostly in Zagreb (<5), Split (<5), Karlovac (<5), and in Tucepi in Makarska area (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 1936 in source Emigration Commission Zagreb.