In Croatia, Lay families are generally Croats (from Djakovo ), rarely Jews. In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and Djakovo.
Prevalence
Only a few people with faimily name Lay live in Croatia today, in five households only. There were 20 of them in the middle of the past century, and their number halved. They are located in two Croatian cities only, in Zagreb (<5) and Djakovo (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 1924 in source Emigration Commission Zagreb.